Tag Archives: sex

Your brain on masturbation

Credit: Pixabay.

Like all things taboo, there are a lot of myths and speculation surrounding masturbation and its effects on the human body.

There’s even a global movement called #nofap, whose followers (mostly men) are abstaining from masturbation in order to reap supposed health benefits, such as enhanced mood, energy, and self-esteem.

While there is still much to learn about how our bodies react to the chemicals and hormones released during sexual release, there are quite a lot of physical and psychological benefits to masturbation, supported by evidence-based science. Most researchers who study sexual health concur that masturbation is a healthy and universal behavior in the human sexual repertoire. 

Masturbation releases feel-good hormones that boost your mood

During masturbation, the brain releases a number of hormones, the most important being dopamine. Also known as the “happiness hormone”, dopamine is heavily involved in the brain’s reward system. Along with oxytocin, a hormone that improves social bonding, dopamine also improves mood and satisfaction.

Other hormones that are released during sexual release also include endorphins, testosterone, and prolactin. These have roles in reducing stress, increasing arousal, and boosting immune system function.

However, it’s yet unclear how these ‘feel good’ hormones differ based on the various forms of sexual release involved (sex vs masturbation or sex with a long-term partner vs sex with a short-term partner).

“I don’t think the science can answer this yet.  It appears that the same types of hormones are released but I think it would be very hard to ever say whether or not they are always released in the same quantity, ratio, or in the same way, regardless of the method to orgasm,” Heather Armstrong, Lecturer in Sexual Health at the Department of Psychology at the University of Southampton in the UK, told ZME Science.

“In terms of outcomes, I think sex (and masturbation) is so contextual that it’s impossible just to tease out one specific thing (i.e., orgasm) and say that that is the one thing causing good outcomes,” she added.

It alleviates stress and anxiety

During sex, hormones like oxytocin cement pair bonding, which is why it’s also known as the “love hormone”. However, even if you experience sexual release by yourself, the boost of oxytocin is associated with lower cortisol levels (the stress hormone) and relaxation.

You fall asleep faster

Many are aware that using masturbation before bedtime can ease one’s way into slumber. That’s because serotonin, oxytocin, and norepinephrine are released during sexual arousal and orgasm — and all three of these hormones are associated with reductions in stress and boosts in relaxation, which promote sleep.

Masturbation may improve immune function

The hormones serotonin and norepinephrine are known to boost REM and deep non-REM sleep, during which immune system proteins known as cytokines are released. These proteins identify infections and inflammation, thus enhancing protection against pathogens and disease recovery.

And also eases or prevents pain

Thanks to its immune system enhancing effects, orgasms can also ease chronic pain, which is often linked to poor immune function.

In a 2013 study published in the journal Cephalalgia, researchers found that sexual activity relieves pain caused by migraines or cluster headaches in up to a third of patients.

The authors of the study claim that endorphins, the body’s natural painkillers, are released during orgasm thus numbing the pain of migraines.

Masturbation isn’t associated with mental illness

Some believe that masturbation can lead to depression in some cases.

At first glance, this doesn’t sound like a ridiculous idea. Like all sexual matters, masturbation is still a taboo topic even in western societies, which have made great strides in the past century in opening up about sex.

Even so, there are many people who have been socialized in religiously strict households and who might feel anxious or guilty when they masturbate as a result.

A 2018 study found that about 62% of male participants who were diagnosed with clinical depression also experienced some form of sexual dysfunction. Among this group, myths about masturbation were prevalent.

However, there is no evidence that suggests masturbation triggers or amplifies depression symptoms. If anything, masturbation should help ease depression thanks to mood-enhancing hormones released post-orgasm.

Low sex drive is a common symptom of depression, and masturbation might help boost it. A 2015 study found that female masturbation enhances sexual satisfaction, and helped women have more orgasms when they had sex with a partner.

Nevertheless, those who feel guilty and very anxious because they masturbate should see a therapist specialized in sexual health.

Masturbation is actually better than sex (for most women)

Sorry to break it to you, guys, but women generally climax quicker and more easily during masturbation than sex. No reason to feel too bad about it though, because it helps both sexes. A 2014 study showed that 35% of women who regularly had orgasms when they had sex also masturbated compared to only 9% of women who could climax regularly during sex but reportedly did not masturbate. As for heterosexual men, 95% climax regularly during sex, according to a 2017 study, regardless of their masturbation habits.

But although studies indicate that self-pleasuring leads to better and more frequent orgasms in relationships, many women believe that their masturbation habits can be perceived as a threat, or even an insult, to their male partner’s sense of sexual prowess. As such, many women refrain from masturbating while in a relationship or avoid proposing the use of sex toys during heterosexual sex with their partners.

This widely held belief was reported by a recent systematic review of hundreds of scientific papers relating to women’s experiences, motives, and perceptions of masturbation, where Dr. Armstrong is a co-author. The review goes on to highlight the most common reasons why women masturbate, including “as a practical alternative when a sexual partner was not around”, “if a woman did not reach orgasm with a partner”, or “as a tool to enhance partnered sex and partnered intimacy”.

Regarding differences between males and females in the positive outcomes for masturbation, Armstrong said: “There is no consensus on whether or not there are significant brain differences between male and females to begin with.  Further, because attitudes toward male vs. female masturbation (both individually and socio-culturally) tend to be quite different, it would be nearly impossible to tease out whether there is a “biological” brain difference, or whether any differences (if there are any) were because of other external factors.”

Is masturbation ever harmful?

Like all things, moderation is key. Excessive masturbation can damage relationships when it becomes the sole outlet of sexual expression. Masturbation can also be physically harmful when people experiment with objects that should have no business near their genitals, nevermind inside them.

“There are very few risks associated with masturbation. Skin irritation may be associated with frequent masturbation if adequate lubrication is not used,” Armstrong said.

There are many myths, however, that claim masturbation can cause prostate cancer (false), is addictive (the American Psychological Association doesn’t recognize masturbation as an addiction), is not safe while pregnant (false), that vibrators cause nerve damage (false), lowers sperm count (false, men don’t have a finite amount of sperm), or lowers testosterone (false — the idea dates from Greek and Roman times, but has no scientific evidence to back it up).

A note on porn

In this day and age, masturbation often goes hand in hand with porn usage. While masturbation, in and of itself, is generally healthy and normal, excessive consumption of video pornography can be associated with some negative effects.

Porn use can hijack the brain’s neural wiring, leading to a surge of unnaturally high levels of dopamine that can damage the reward system. Long-term, frequent use of pornography is also associated with sexual dysfunction, lower levels of marital quality and commitment to one’s romantic partner. Some researchers have gone as far as likening porn use to substance abuse.

“It’s very difficult to separate out porn use from masturbation.  Also, there could be differences between porn use without masturbation vs. masturbation without porn use vs. porn use with masturbation without orgasm vs. porn use with masturbation including orgasm.  I think the jury’s still out as well on the positive and negative effects of porn use.  It appears that for the majority of people, porn use is not problematic.  For the minority that do experience problematic porn use, it’s difficult to say whether porn itself leads to problematic use, or if the problematic use is the result (or a side effect) of other factors,” Armstrong said.

Bottom line: Masturbation is a healthy, normal, and very common (universal) form of human sexual behavior. However, sometimes it can have negative effects on mental health if people feel guilty about it, which is why it’s important to normalize it and have conversations about it. Porn use is a different discussion, but in order to reap the full benefits of masturbation, one should stay clear of excessive consumption of pornography.

One gene can turn mosquitoes from females to males, which don’t bite

Researchers at Virginia Tech have found that they can turn female Aedes aegypti mosquitoes into males by tweaking a single gene in their DNA.

Image via Pixabay.

The findings could help us reduce the spread of mosquito-borne diseases. Female mosquitoes need to bite mammals in order to absorb their blood — which is converted into nutrients for their eggs. Males, on the other hand, don’t. They spend their days sipping on nectar.

Mosquito bites create an ideal opportunity for diseases such as malaria, Zika, or Dengue to spread, as they involve a small amount of the insect’s saliva entering the victim’s tissues. Shifting the ratio towards males can thus nip such diseases in the bud.

Changing demographics

“The presence of a male-determining locus (M locus) establishes the male sex in Aedes aegypti and the M locus is only inherited by the male offspring, much like the human Y chromosome,” said Zhijian Tu, a professor in the Department of Biochemistry in the College of Agriculture and Life Sciences, lead author of the study describing the process.

“By inserting Nix, a previously discovered male-determining gene in the M locus of Aedes aegypti, into a chromosomal region that can be inherited by females, we showed that Nix alone was sufficient to convert females to fertile males. This may have implications for developing future mosquito control techniques.”

The team produced several such gene-modified mosquitoes that express an extra copy of the Nix gene that is activated by its own promoter.

This sex conversion was found to be highly effective and “stable over many generations in the laboratory”, the team explains, suggesting that it would be useful in wild populations without constant reintroduction of modified mosquitoes.

However, these converted males can’t fly naturally. In order to remedy this, the team found that a second gene (myo-sex) needs to be added to the M locus as well. The team inactivated the myo-sex gene in wild-type males to confirm its function — and these insects lost their ability to fly.

Flight is important for these sex-changed insects as mosquitoes rely exclusively on flight for feeding, mating, and escaping predators. In other words a flightless mosquito, no matter how well-engineered, won’t do us much good. This being said, however, the authors report that sex-changed males were still able to father sex-converted offspring if they were presented with an anesthetized wild female.

All in all, the Nix gene has great potential as a tool to reduce the population of biting mosquitoes, and thus, the spread of disease. However, there’s still a lot of work to be done in the lab before such insects can be released into the wild.

The paper “Nix alone is sufficient to convert female Aedes aegypti into fertile males and myo-sex is needed for male flight” has been published in the journal Proceedings of the National Academy of Sciences.

The clap is making a comeback — as are syphilis and chlamydia

Syphilis, gonorrhea, and chlamydia are catching on with more and more people, says the Centers for Disease Control (CDC).

Image credits Paul Sableman / Flickr.

Rates of these sexually-transmitted diseases (STDs) are on the rise, the CDC warns in a recent report. Both the number of infections per capita and the total number of cases for all three STDs have been steadily rising since the 2000s. All in all, the report adds, infection rates are at their highest level since the CDC began keeping track of chlamydia cases in 1984.

A social endeavor

The CDC says that the increase isn’t automatically attributable to a bump in the number of infected individuals. As testing becomes more commonplace, each state naturally reports higher numbers of positive results. The observed increase, the CDC explains, can be caused by more states reporting on cases of these three STDs, or by them improving testing practices.

Still, the recent increases from year to year, when testing practices have not dramatically changed, likely indicate an increase in the number of infections themselves, the authors note.

For chlamydia, they report, increased testing and the refinement of testing methods (the report notes to the expanded use of “nucleic acid amplification tests” between 2000 and 2011 in particular) likely drive most of the observed increase in cases. This view is further reported by a separate CDC document that found no statistically significant increase in the chlamydia rate between 1999 and 2012.

That being said, the current report does note that the current prevalence of chlamydia is “surprising”, especially among young, sexually-active women. Around 4% of women aged 15 to 24 tested positive for the disease, compared to 1% of men in the same age group and under 1% for both men and women in other age groups. Chlamydia is generally asymptomatic in women, the report notes, meaning that many then act as unwitting carriers of the disease to male partners.

Syphilis and gonorrhea are less common, the report notes. However, both have seen recent rises in prevalence, after falling to historic lows in the early 2000s. Gonorrhea infections in particular increased by 82.6% since reaching a historic low in 2009. The CDC suggested that “multiple factors” are at play, including “drug use, poverty, stigma, and unstable housing, which can reduce access to STD prevention and care,” “decreased condom use among vulnerable groups,” and “cuts to STD programs at the state and local level.”

Both increases seem to be primarily driven by “men who have sex with men” (MSM, a stated-sexual-preference-neutral term used by the CDC and other public health organizations). MSM accounted for the majority of primary and secondary syphilis diagnoses since at least 2014, the report adds. By 2015, MSMs were 24 more likely to have gonorrhea than women, and 31 times more likely than “men who have sex with women.” In a companion release, the CDC suggested that “multiple factors, including individual behaviors and sexual network characteristics,” may determine the high prevalence of STDs among MSM. Those network characteristics included “high prevalence of STDs, interconnectedness and concurrency of sex partners, and possibly limited access to healthcare,” as well as socioeconomic disadvantage among certain MSM subpopulations.

One of the most heartbreaking findings from the study is a dramatic increase in syphilis cases among newborns (congenital syphilis); the reported number of such cases nearly tripled since 2014 to 1,306 cases in 2018.

Antibiotic-resistant gonorrhea is also featured in the report. The CDC explains that over half of such infections reported in 2018 were resistant to at least one antibiotic. However, the centers also explain that ceftriaxone, the ‘first line of defense against gonorrhea’, remains effective at its intended role.

The full report “Sexually transmitted diseases Surveillance 2018” is available here.

Women are just as aroused by pornography as men, largest study of its kind shows

A review of 61 brain scanning studies contradicts the widespread belief that men enjoy sexual imagery more than women.

Although there was never really strong science behind this idea, men are typically seen as being more interested in sex than women. Questionnaire-based studies have suggested that men find erotic images more arousing than women do, which seemed to play into the same narrative — women are more likely to require an emotional connection before they can become aroused.

The first brain scan studies seemed to validate the questionnaires. Despite major differences from individual to individual, some studies seemed to suggest that men are more interested in pornography. However, a more scrutinous look can find some important shortcomings for these studies. Most importantly, they work with small sample sizes and are prone to drawing conclusions from data which may be owed to random variations.

In order to fix that issue, a team led by Hamid Noori at the Max Planck Institute for Biological Cybernetics in Tübingen analyzed the results from all the brain-scanning studies that have ever been published on this issue. In total, the studies had a combined sample sized of 2,000 — still not massive, but sufficient to draw some more reliable conclusions.

They found no important differences between how men and women react to pornographic images.

“Neuroimaging studies suggest differences in the underlying biology of sexual arousal associated with sex and sexual orientation, yet their findings are conflicting,” the study reads. “Following a thorough statistical review of all significant neuroimaging studies, we offer strong quantitative evidence that the neuronal response to visual sexual stimuli, contrary to the widely accepted view, is independent of biological sex.”

Women do watch less pornography than men (a roughly 80%-20% split), but that is owed to non-biological factors. For starters, the entire market is tailored for men, and the stigma of watching pornography is also greater for women than men.

Of course, this study also has significant shortcomings, which the researchers also admit. For starters, the study was limited to functional neuroimaging experiments — brain scans that only show activity at the level of large anatomical structures, meaning there could still be differences at smaller levels that don’t get picked up. There is also a lack of reporting on null results, which can tweak the results, and the quality of the considered studies varied significantly.

Overall though, this makes a lot of sense. Humans, like all mammals, react to sexual visual stimuli. But there is another consideration: just because there is a biological reaction doesn’t necessarily mean you’re “turned on” — our brains are often more complicated than our genital desires.

For instance, men can be physically aroused and have erections without being turned on. In some cases, even unwanted stimulation (rape) can produce unwanted arousal, in both men and women. Our sexual arousal is not just a button you can switch on or off.

The study has been published in PNAS.

Credit: Pixabay.

Both males and females perceive women wearing makeup as more open to casual sex — and they’re wrong

Credit: Pixabay.

Credit: Pixabay.

A new study found that both males and females perceive women wearing makeup as more attractive. They also see a woman’s makeup as a sign of greater interest in casual sex, something which scientists say doesn’t actually reflect reality. Psychologists call this a ‘false signal’.

Sociosexual orientation, or sociosexuality, is the individual difference in the willingness to engage in sexual activity outside of a committed relationship. Evolutionary personality psychologists classify men and women on sociosexual orientation between the extremes of unrestricted (more comfortable with casual sex with different partners) and restricted (prefer sex with a partner in a long-term, exclusive relationship).

Compared to sociosexually restricted individuals, people with a more unrestricted sexuality are more likely to engage in sex at an earlier point in their relationship, have sex with more than one partner a time, and be involved in relationships characterized by less investment, commitment, love, and dependency.

Just like any other personality trait, sociosexual orientation is relatively stable over the course of an individual’s lifetime. In other words, people are generally either sociosexually restricted or unrestricted, in various degrees, for most of their lives. And, while men, in general, are more unrestricted in sociosexual orientation than women, the variance within each sex is much greater than the variance reported between men and women.

But we can sometimes misinterpret a person’s personality traits, including how sexually open or reserved they are. Carlota Batres, a psychologist at Gettysburg College in the US, along with colleagues, asked 182 people to judge the sociosexual orientation of 69 young adult women of European descent.

The more makeup the women pictured in photos were wearing, the more likely they were to be perceived as attractive, but also sexually unrestricted by both male and female participants.

When the 69 women were surveyed regarding their sociosexual orientation, the researchers could not find any association between the trait and the time or resources spent on makeup. Simply put, makeup had no influence on how sexually open a woman actually was.

“Targets’ self-reported sociosexuality was not associated with their makeup habits, with observer ratings of the amount of makeup they wore, or with observer ratings of their sociosexuality when attractiveness was controlled. Thus our study shows that people use makeup as a cue for perceiving sociosexuality but that it is an invalid cue,” the researchers reported in the journal Personality and Individual Differences.

So it seems like this is an example of wishful thinking — men who see an attractive female may be too optimistic regarding the woman’s sociosexual orientation and, in the grand scheme of things, her willingness to mate with the man. Attractive qualities, not makeup itself (an enhancer), might constitute the false signal.

Norwegian elders lead in masturbation

This article has been republished with permission from Science Nordic. Author: Nancy Bazilchuk, based on an original article by Siw Ellen Jakobsen.

More than 90% of Norwegian men between the ages of 60 and 75 are sexually active, as are almost 75% of Norwegian women.

Few people study the sex lives of the elderly. But once they do, they find some surprises, says Bente Træen, a professor of health psychology at the University of Oslo.

“Researchers are like other people. We are raised to think of sexuality as something for the young and the good looking,” she said. Now, she says, they know better.

Træen worked with a group of European researchers to study sex among the European elderly.

Many masturbate

Træen and researchers from five other countries have compared the sexual activity of people between the ages of 60 and 75 in Norway, Denmark, Belgium and Portugal in a major study. Now the team is beginning to publish its results.

She says the group’s findings are unexpected, even for people who are accustomed to studying sexual habits.

“I am surprised at how many people are sexually active. It’s not that I’m comparing what we found to previous studies, because there aren’t that many other studies. It’s more about the societal myths we have about the elderly and sex,” she says.

Many people in the study reported that they masturbate and often have intercourse. What was also surprising was that the elderly in the study were generally satisfied with their sexuality, according to Træen.

Norwegian men and women were at the top of the list when it came to masturbation.

Fully 65% of men and 40% of women said they had masturbated in the previous month.

In contrast, very few Portuguese men and women say they have masturbated.

Lots of intercourse in Portugal

Men in Portugal, on the other hand, are at the top when it comes to having intercourse, according to the survey.

The Portuguese say they have intercourse one to three times a week. This is far more frequently than men in Norway, Denmark and Belgium. In these three countries, men report having intercourse about two to three times a month.

Thus, it is perhaps not surprising that Portuguese men are most satisfied with their sex life of all the men in the survey.

Nordic women in the survey reported being most satisfied with their sex life.

Træen interprets these results as reflecting the gender equality situation in the different countries.

“In Norway, women are much more used to negotiating with regards to their own sexuality. The Mediterranean countries are much more traditional when it comes to gender roles. The typical Portuguese man has access to a partner that he has intercourse with — and he is very satisfied with that. While we in the north may have intercourse less often and masturbate more, intercourse is what really matters in Portugal,” Træen said.

Poorer data from Portugal

Træen and the other researchers first conducted recruitment interviews by phone to find a representative selection of both sexually active and inactive individuals for the survey. These individuals then were sent a questionnaire by mail.

However, there was a big difference in participation from the different countries.

In Norway, 68% agreed to participate. In Portugal, only a quarter of respondents contacted by phone said they would be willing to participate in the written questionnaire. Many people also changed their minds after saying yes on the phone. Træen thinks this makes for some uncertainty regarding the data from Portugal.

“The response rate in Norway was much higher than we had thought it would be. I actually expected more people to drop out of the survey. But the response rate in Denmark and Belgium response was also quite good. It’s possible that people in Portugal found some questions offensive, although we obviously tried to avoid this problem,” she said.

Desire diminishes but does not disappear

Træen was also the main author of another recent study on older people’s sexuality. Here, researchers asked 75-year-olds in the same four countries about their sex drive as compared to ten years ago. Most people responded that it was a little less or the same.

“Sexual desire diminishes with age, but that does not mean it disappears. How satisfied you are with your sex life changes as you age. As a young person, you most appreciate the ‘gymnastic side’ of sex and pleasure related to genital contact. When you are older it’s more about having a comfortable relationship with someone, and being touched and kissed,” she said.

There is an important difference between the sexes here. Health is often what decides if men still have sexual desire, while for women, interpersonal relationships are the most decisive in determining their level of desire.

Health care systems must recognize the need for sex

This new information on older people’s sexual habits shatters old myths, Træen says.

“Older people are not asexual. That means that sex must be higher on the agenda as an issue in the planning of health care for older adults,” she concluded.

Almost 40% of people aged 65 to 80 are sexually active, but few are open about it

Many believe that once you reach a certain age, there’s no more dancing in the sheets — but sex isn’t just for the young and restless. Case in point, four in ten people between ages of 65 and 80 are sexually active, according to recent findings by the National Poll on Healthy Aging. The poll highlights gender and health-related divides on key aspects of sexual health, and also informs that the elderly rarely talk about sex with their doctors — this may be problematic since many older adults consume over-the-counter supplements that might interact with their medication.

Many seniors are eager to have sex — but they need to talk more about it with doctors

The poll was conducted by the University of Michigan Institute for Healthcare Policy and Innovation on a nationally representative sample of 1,002 people. Among the key findings:

  • Nearly three-quarters of people aged 65-80 have a romantic partner, and 54 percent of those with a partner are sexually active.
  • About 20 percent of men and 3 percent of women in the same age group said they took supplements or medication to improve sexual function in the past two years.
  • Whether or not they are sexually active, two-thirds of older adults say they’re interested in sex, and more than half say sex is important to their quality of life.
  • When asked whether they’re satisfied with their sex life, 73 percent of the polled individuals answered ‘yes.’
  • Only 17 percent of older adults said they have talked with their doctor or other healthcare providers about sexual health in the past two years. In most cases, the topic was brought up by the poll’s respondents signaling that clinicians might want to be more proactive with conversations about sex with their older patients.

“Sexual health among older adults doesn’t get much attention but is linked closely to quality of life, health and well-being,” says U-M’s Erica Solway, Ph.D., co-associate director of the poll. “It’s important for older adults and the clinicians who care for them to talk about these issues and about how age-related changes in physical health, relationships, lifestyles and responsibilities such as caregiving, affect them.”

Solway and colleagues learned that there can be sharp differences in the respondents’ sex lives depending on their health, age, and gender. For instance, 45 percent of the respondents who are in excellent, very good, or good health reported being sexually active but only 22 percent of those who are in fair or poor health responded the same way. What’s more, only 28 percent of those with fair or poor health said they were extremely or very satisfied with their sex lives.

As expected, those in older age groups were far less sexually active. Respondents between ages 65 and 70 were twice as likely as those in their late 70s to be sexually active. A third of those in their late 60s said they were extremely or very interested in sex, compared to just 19 percent in their late 70s.

Women were less likely than men to be sexually active (31 percent vs 51 percent of men). On the upside, women were more likely to be extremely or very satisfied with their sex lives than men. About 84 percent of older men said sex was an important part of a romantic relationship, 69 percent of older women agreed with that statement. The biggest gender difference, however, is in term of interest in sex. Half of the men aged 65 to 80 said they were extremely or very interested in sex whereas only 12 percent of women in the same age range agreed. Perhaps this may be due to the fact that men continue to be sexually reproductive whereas women of the same age are now infertile.

“This survey just confirms that the need for and interest in sexual intimacy doesn’t stop at a certain age,” says Alison Bryant, Ph.D., senior vice president of research for AARP. “Although most older adults say that they would talk with their doctor about sexual concerns, health care providers should routinely be asking all of their older patients about their sexual health and not assume that bringing up the issue will offend or embarrass them.”

Alcohol might lead to postsexual regret more than ecstasy or marijuana

A new psychological study reveals that drinking might lead to post-sex regret more than ecstasy or marijuana consumption.

Via Pixabay/bridgesward

According to the scientists, alcohol is more strongly associated with heightened perceived sexual effects like perceived sexual attractiveness of self and others, sexual desire, length of intercourse, and sexual outgoingness.

The paper, published in the journal Psychology & Sexuality, says that male participants experienced sexual dysfunction when consuming alcohol or taking MDMA (the main psychoactive ingredient in ‘ecstasy’ pills), but female participants suffered sexual difficulties when smoking pot. Interesting, right?

“A lot of studies suggest that the use of various drugs increases the chances for sexually risky behavior, but few have examined the actual sexual effects of drugs,” said Joseph J. Palamar of New York University, an author of the study, to the Psypost.

Ecstasy pills
Via Wikipedia

“Whether or not someone uses a condom while high is important. However, limiting research to this behavior really ignores the actual sexual responses associated with drug use that may in fact influence one’s decision to have sex with or without a condom.”

Scientists gathered interviews from 679 young people between the ages 18 and 25 right outside New York’s nightclubs and dance festivals. They found out that alcohol made them feel sexier than the other drugs.

“Each drug is associated with its own level of sexual risk,” said Palamar. “Alcohol is likely the riskiest as use is not only so common but also promoted throughout much of society. Even if sex itself isn’t risky while on alcohol, post-sex regret is extremely common as users may hook up with someone they normally wouldn’t have sex with.”

There was no surprise that ecstasy was found to be the drug most associated with an increased body and sex organ sensitivity, as well as increased sexual intensity. After all, its name speaks for itself.

The study has its limitations though: researchers only relied on self-reports. Another thing we ought to consider is that youngsters often mix these drugs up, and it’s rather difficult to say what substance has which effect. And let’s not forget that… well, users are prone to forget things when under the influence of psychoactive substances.

Fruit fly.

Neuron cluster which can override sleep identified in the fruit fly brain

Certain neurons in the brains of male fruit flies will suppress the animal’s sleep if they have any female to court nearby.

Fruit fly.

Image credits John Tann / Flickr.

Who here hasn’t had to forgo the sweet embrace of sleep when something important pops up — a paper due in the morning, a book you just can’t put down. Or, if you’re a male fruit fly, because there’a a change you might get some action.

A team of researchers from the Sidney Kimmel Medical College at Thomas Jefferson University found that like humans, fruit flies (Drosophila melanogaster) can keep themselves awake if something important pops up. More specifically, they report that a certain group of neurons in the males’ brains can suppress their sleep so they can court female flies.

Up all night to get lucky

The study started from the observation that although male flies usually spend most of the night awake trying to court nearby ladies, those who have recently mated several times (and thus have a low sexual drive) tend to ignore females and simply go to sleep.

It would suggest that something in the fly’s brains has to (consciously or unconsciously) decide what was more important to the fly at one point — sex or sleep. But nobody knew exactly how this process unfolded, and that’s what the team set out to understand.

“The idea that sleep and courtship might compete with each other is intuitive but had not been studied experimentally, and the underlying neural mechanisms had not been explored. We wanted to know how the sleep drive and sex drive compete to determine behavior,” says Kyunghee Koh, PhD, Associate Professor of Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University and senior author on the study.

The team zeroed in on a bunch of neurons dubber MS1 (male specific 1) that seem to be at the root of this process. MS1 neurons aren’t part of any previously known groups of neurons which play a part in male sexual behavior, but work by keeping the males awake so they can ply their charm. They release octopamine, a neurotransmitter similar in function to noradrenalin, which will keep male flies awake in a sexual setting. Experiments showed that silencing the MS1 cluster caused males to go to sleep even if there were females around, and artificially activating the neurons kept males awake even in the absence of females.

Interestingly enough, while females have the same bunch of neurons they don’t seem to function the same — activating or inactivating the cluster had no effect on the females’ sleep.

We don’t yet know whether there are similar mechanisms functioning in our brains, but we do know that noradrenalin creates wakefulness in humans. This would suggest that the neurotransmitter plays a key role when we’re trying to consciously suppress sleep, the team notes.

But until we get a definitive answer on that, the team wants to identify which neuron communicate directly with the MS1 cluster, examine how their activation leads to sleep suppression and how MS1 neuronal activity is regulated.

The full paper “Identification of octopaminergic neurons that modulate sleep suppression by male sex drive” has been published in the journal eLife.

Peacock.

Sleeping around makes it hard to speciate by mixing genes, paper shows

Promiscuity may work against speciation by homogenizing a population’s gene pool, a paper from the University of Bath’s Milner Centre for Evolution reports.

Wild Rabbits.

I’ll let you make the joke for this one.
Image credits Holger Langmaier.

In order for one group to speciate (split off into new species), there has to be a certain level of genetic isolation going on. Darwin said that over time, as environmental factors collide with the genetic make-up of each population, natural selection would favor the best-adapted individuals, who would pass on their genes more readily — thus favoring speciation. This is really good if you want to become adapted to the particular conditions in your plot of land.

But efficient Darwinism isn’t the only hand shaping genomes around the world. Other models, such as Fisher’s runaway selection models, take into account sexual selection. In short — males like females, females like what they like, so strong horns make way for flashier horns to give males a better shot at getting some action. This way, arbitrary traits which can actually make animals less adapted (think of the peacock’s ridiculously impractical drab) become valuable assets as they improve access to mates.

Peacock.

#Yolo.
Image credits Christy Mesker.

Theories like Fisher’s brought into discussion the fact that sexual preferences, especially on the part of the females who tend to be pickier in regards to mates, can become a huge driver of speciation. Preferences can vary quite wildly from place to place and as genomes get tuned more towards delivering the goods at the expense of efficiency, overall genetic diversity rises setting the stage for speciation — or at least that’s how the theory goes.

But this conventional wisdom might not be spot-on, according to a new paper published by researchers at the University of Bath, Cardiff University, and the Max Planck Institute for Ornithology. By tracking microsatellite data for 79 populations of 10 plover species (Charadrius) and the genetic structure of 136 shorebird species, the team found that a propensity for promiscuity makes a population’s genes less diverse. They report that polygamous bird species (those who breed with several partners each season) are less genetically diverse than monogamous (only one partner per season) species — lowering the chances of speciation.

“Our findings suggest that because of the pressure to find more than one mate, polygamous shorebirds may search large areas and therefore spread their genes as they go,” said first author Josie D’Urban Jackson, who is jointly supervised at University of Bath and Cardiff University.

“This means they effectively mix up the gene pool by diluting any genetic differences between geographically distant locations, so that populations are less likely to diversify into new species over time.”

Monogamous species only have to find one mate to partner up with each season, and generally tend to re-visit the same breeding sites throughout their life. This means they’re better adapted to local conditions and more genetically isolated as there is little to no influx of outside genes. All this makes monogamous species more likely to speciate.

Promiscuous species on the other hand travel far and wide to sow as many oats as they possibly can — but it’s not a case of first come, first served. Jackson’s supervisor at the University of Bath’s Milner Centre for Evolution, Tamás Székely, says that polygamous birds can travel hundreds of kilometers at a time to find a mate they like.

“You might think that birds choose mates arbitrarily if they are promiscuous, but most individuals prefer a certain type, just as some humans might prefer blonde or dark hair in a partner,” said Professor Tamás Székely.

This makes promiscuous populations mix their genes even over huge distances, while their monogamous counterparts can remain relatively distinct a stone’s throw away.

“For example, in Madagascar, we found that the polygamous plovers were similar across the whole island, whereas the monogamous plovers have distinct genetic composition between nearby locations — showing the same pattern that our larger scale study just confirmed.”

The paper “Polygamy slows down population divergence in shorebirds” has been published in the journal Evolution.

 

Antlers.

Men trophy hunt to show off to the ladies, new research found

Why do some humans go after the biggest animals they can find? And how can these hunters be turned away from killing what are often endangered or threatened beasts? One trio of researchers found it’s all about bragging — or shaming.

Antlers.

Image credits Michael Bieri.

For a really long time in human history, supermarkets surprisingly weren’t a thing. So if you wanted some meat to go with your nuts, berries, and assorted veggies, boy you were in for an adventure — it was either hunting something alive or scavenging (which usually meant fighting something alive which had fangs). Long story short, it was dangerous, but we had to do it for the food.

There is one kind of hunting that flies in the face of this risk-reward dynamic animals have with subsistence hunting, however. Some human hunters go after the biggest, meanest, most dangerous animal around, even when they don’t want to eat it. Needless to say, such hunting can have devastating consequences for wildlife populations. So why do some people spend huge sums of money to kill big game that’s usually on the brink of extinction anyway? It doesn’t make any sense.

The answer, according to a trio of researchers, is sex.

What.

The fact that it doesn’t make sense is half the point here, the team explains. The other one is that it is expensive. Put them both together and what you get is “this costs a lot, I get nothing out of it, and now I am going to do it. Look how cool I am.” In short, it’s all about getting bragging rights. The pricey hunt is meant to show off a male’s high social status to competitors and potential mates. The theory would offer an evolutionary explanation for why humans kill animals they don’t need to, and suggests a possible tactic for discouraging that behavior in the future.

“Policy debate about [trophy hunting] benefits and costs focuses only on the hunted species and biodiversity, not the unique behaviour of hunters,” the authors write.

Lead author Chris Darimont, Hakai-Raincoast professor at the University of Victoria in British Columbia and his team describe human beings as “superpredators” because they’re not bound by the typical rules of other carnivores in the animal kingdom. The average predator “typically picks prey that are newly born (the juveniles) or nearly dead (the sick and weak animals, the substandard animals in populations) and they eat them,” they added. “And this really bizarre, unique predator, [the] human being, kind of does the opposite. We target the large; we target animals for characteristics that have nothing to do with their nutritional value; we target animals with big horns or antlers.”

To find out what evolutionary drive powers trophy hunting, the team compared this behavior to the habits of “traditional hunter-gatherers” — modern populations whose lifestyles resemble those of ancient humans. Darimont pointed out that in the Meriam population of Australia, men and women both hunt for green turtles but employ different methods.

We can do it the sensible way, or the right way

Ego.

Look at this handsome guy!
Image credits cortto / Flickr.

Whereas the women employ a safe and easy method, by capturing turtles who come ashore to lay eggs, men take a complicated, expensive, and dangerous route. They take to the sea on boats then dive in dangerous waters to hunt the same turtles on their own turf. Even worse, the men often have to share the meat they hunt with the community, rather than keeping it for their family.

Still, the men keep hunting this way because they get another (more evolutionary relevant) advantage. They show that they can mobilize the resources to undertake such a costly and dangerous task, which shows they can provide for their offspring, potentially making them more attractive to mates. This behavior is known as “costly signaling behavior,” and the Meriam males use it to gain social standing. The team reports that the turtle hunters get married earlier, to “higher quality” mates, and generally have more surviving children than their peers.

With the advent of social media, these hunters have more opportunity to brag — but they’re also opening themselves to shaming by critics. Public outcry, the team points out, may be a key tactic to stemming such behavior.

“If these hunters are hunting for status essentially, there’s nothing like shame to erode status,” Darimont said.

“So where the internet might fuel this kill-and-tell generation, it might also provide a vehicle for those opposed to trophy hunting to emerge with a powerful strategy.”

The full paper “Why men trophy hunt” has been published in the journal Biology Letters.

Ladybugs.

If you like having sex, you should thank pathogens for making it possible

The arms race between pathogens and the organisms they infect may be the fundamental reason why animals have taken to having sex and then stuck with it, a new paper reports.

So why do we have sex? Well, it’s obvious isn’t it — we do it to make more humans. But there is a small chink in that explanation, something which has been bothering evolutionary geneticists for about as long there have been any around: sexual reproduction is hard work, whereas asexual reproduction is easy and much more efficient — so why bother with it?

Ladybugs.

Image via Pixabay.

That’s something we’ve all asked ourselves at one point or another but Dr. Jack da Silva and James Galbraith from the University of Adelaide have actually set out to get an answer. After using a computer model to simulate how the genomes of Caenorhabditis elegans (non-parasitic roundworms) shift throughout several generations, the duo suggests that sexual reproduction imposed itself because organisms needed to constantly adapt their genomes to fight off co-evolving pathogens.

“Asexual reproduction, such as laying unfertilised eggs or budding off a piece of yourself, is a much simpler way of reproducing,” says Dr da Silva, Senior Lecturer in the University of Adelaide’s School of Biological Sciences.

“It doesn’t require finding a mate, and the time and energy involved in that, nor the intricate and complicated genetics that come into play with sexual reproduction. It’s hard to understand why sex evolved at all.”

One decades-old theory has been attracting more attention recently, da Silva said. Known as the Hill-Robertson Interference, it holds that sexual reproduction evolved because it allows DNA recombination between mates, allowing offspring to ‘hoard’ more beneficial mutations. In the case of asexual reproduction, where there is no pooling of genes, beneficial mutations compete with each other and natural selection grinds down.

But de Silva says this theory doesn’t explain why sexual reproduction would be maintained in a stable, well-adapted population — where maintaining the status quo makes more evolutionary sense.

 

“It is hard to imagine why this sort of natural selection should be ongoing, which would be required for sex to be favoured,” he says.

“Most mutations in an adapted population will be bad. For a mutation to be good for you, the environment needs to be changing fairly rapidly. There would need to be some strong ongoing selective force for sex to be favoured over asexual reproduction.”

The team’s suggestion is to bring another, less influential evolutionary theory into the mix. Known as the Red Queen theory, it holds that because bacteria, viruses, or parasites are continuously trying to adapt and overcome our natural or artificial defenses, our genomes are also trying to keep one step ahead by continuously mutating, becoming more resistant to them.

‘Good enough’ is better than ‘the best’

While we may be really well adapted to our environments, there’s a constant sort of biological arms race going on. Staying unpredictable — by having the ability to develop new mutations and pool them in offspring — thus becomes more advantageous than reaching a hypothetical ‘best-adapted’ genome and keeping with it.

So in the end, organisms may have chosen sexual reproduction over cloning because, although it’s harder and (on those lonely Saturday nights) more frustrating to pull off, it keeps us all similar but different enough so the germs can’t get us all in one shot. Which I feel is win for us.

“These two theories have been pushed around and analysed independently but we’ve brought them together,” says Dr da Silva. “Either on their own can’t explain sex, but looking at them together we’ve shown that the Red Queen dynamics of co-evolving pathogens produces that changing environment that makes sex advantageous through the simple genetic mechanism of the Hill-Robertson theory.”

“This is not a definitive test but it shows our model is consistent with the best experimental evidence that exists.”

The paper “Hill-Robertson Interference Maintained by Red Queen Dynamics Favours the Evolution of Sex” has been published in the Journal of Evolutionary Biology.

Two-day long sexual ‘afterglow’ helps couples bond and feel more sexually satisfied after the deed

A study of newlywed couples found that partners show a sexual ‘afterglow’ after the deed which can last up to two days. This afterglow was linked with greater relationship satisfaction and a lower decline in satisfaction over time.

Image credits Alexas_Fotos / Pixabay.

Sex is a great couple activity to cement a relationship and help you bond with your partner. Even better, you don’t even have to leave the comfort of your house to do it. For all it’s usefulness to the couple and the obvious other benefits it brings to the table/bed/counter, people don’t usually have sex with their partners every day, but rather once every few days. So Andrea Meltzer, a psychological scientist at the Florida State University, and her team, theorized that the benefits of doing the do extends for longer than a day — providing a short-term boost to sexual satisfaction and promoting pair bonding between the partners, increasing overall relationship satisfaction over the long term.

“Our research shows that sexual satisfaction remains elevated 48 hours after sex,” says Meltzer, who was first author on the study.

“And people with a stronger sexual afterglow — that is, people who report a higher level of sexual satisfaction 48 hours after sex — report higher levels of relationship satisfaction several months later.”

Self-reported love

To test their theory, the team looked at data gathered from “two independent, longitudinal studies”, one with 96 newlywed couples and the other with 118 newlywed couples. These couples had completed at least three consecutive days of a 14-day daily diary task as part of a larger study looking at their daily sexual activity as well as sexual and marital satisfaction “at baseline” and 4 to 6 months later.

Every night before going to bed, the newlyweds were asked to independently report whether or not they had sex day with their partner that day. They also had to use a 7-point scale (1=not at all, 7=extremely) to rate how satisfied they were with their sex life, their partner, the relationship, and their marriage that day. They also completed three measures of marriage quality at the beginning of the study and during a follow-up session 4 to 6 months later.

Although the answers varied considerably among participants, on average they reported having sex 4 times during the two-week study. The team found a link between sex on a given day and greater self-reported sexual satisfaction over the next one or two days. So every ‘sex’ made the participants feel better about their sex lives for up to 48 hours. This link held strong throughout gender and age groups even after the team accounted for other factors such as personality traits, sexual frequency, or length of relationship.

All couples experienced a decline in marital satisfaction during the baseline and the follow-up session. But more importantly, participants who reported a relatively high level of sexual afterglow reported both higher initial marital satisfaction and less decline in satisfaction over the first 4 to 6 months of their marriage. The findings are consistent with those reached by the two independent studies, which Meltzer and her colleagues say provides strong evidence in favor of the sexual afterglow.

“This research is important because it joins other research suggesting that sex functions to keep couples pair bonded,” Meltzer concludes.

So what does this mean? Well, not only will sex feel good and make you feel life’s that one shade brighter afterwards, but it will also help maintain relationship quality over time. What more do you need? Grab that special someone and go bond the feathers out of each other.

The full paper “Quantifying the Sexual Afterglow: The Lingering Benefits of Sex and Their Implications for Pair-Bonded Relationships” has been published in the journal Psychological Science.

From married couples to the hook-up kids, Americans are having less sex across the board

A new survey found that Americans aren’t having as much sex as they used to. Married couples or those who cohabitate had sex 16 fewer times on average between 2010-2014 compared to 2000-2004. Overall, Americans had sex about 9 fewer times per year in 2010-2014 compared to 1995-1999.

Well, presumably the other two are still going strong.
Image credits GanMed64 / Flickr.

Based on data collected from the General Social Survey which has recorded (among other things) the sexual behavior of more than 26,000 American adults since 1989, a team from the San Diego State University found that Americans today just aren’t getting down between the sheets as much as previous generations did.

“These data show a major reversal from previous decades in terms of marriage and sex,” said Jean M. Twenge, the study’s lead author and professor of psychology at San Diego State University.

“In the 1990s, married people had sex more times per year than never-married people, but by the mid-2000s that reversed, with the never-married having more sex.”

Twenge says that the main factor driving sexual habits seems to be the birth cohort (i.e. generation), with those born earlier in the 20th century having had more sex on average compared to their younger peers at the same ages. But it may not be so much an issue of Americans having less sex with their partners, but rather a lack of partners to get frisky with — Twenge’s previous research found that Millennials/Generation Y had fewer sexual partners on average compared to members of the Generation X at the same age.

“Despite their reputation for hooking up, Millennials and the generation after them [iGen or Generation Z] are actually having sex less often than their parents and grandparents did when they were young,” said Twenge.

“That’s partially because fewer iGen’ers and Millennials have steady partners.”

Age is also an important factor. People in their 20s report having sex in excess of 80 times per year, a figure which declines to 60 times per year by age 45, and goes all the way down to 20 times per year by age 65, the team reports. So individuals’ average sexual frequency declines by 3.2% each year after the peak at age 25.

But it’s not only kids failing at attracting the opposite sex, Twnege says. It’s also happening to married couples.

“Older and married people are having sex less often — especially after 2000,” he said.

“In a previous paper, we found that the happiness of adults over age 30 declined between 2000 and 2014. With less sex and less happiness, it’s no wonder that American adults seem deeply dissatisfied these days.”

While the study doesn’t offer any evidence as to why this is happening, Twenge says that it’s not due to excessive workloads — Americans who worked more hours actually had sex more often than their peers. Which my actually explain why they work so hard.

The full paper “Changes in American Adults’ Reported Same-Sex Sexual Experiences and Attitudes” has been published online in the journal Archives of Sexual Behavior.

Have more sex and leave stress at the office to improve your work life

A new paper from the Oregon State University found that an active and healthy sex life can boost employees’ job satisfaction and productivity, evidencing the need for a good work-life balance, the authors report.

Image credits Michal Jarmoluk.

Getting busy between the sheets could be just the thing to make you enjoy your job more, says Keith Leavitt, associate professor in OSU’s College of Business. He and his team looked at the relationship between the work and sex habits of married employees and found that those who got some love at home unknowingly received a boost in workplace the next day — when they were more likely to immerse themselves in the tasks at hand and drew more enjoyment in their work.

“We make jokes about people having a ‘spring in their step,’ but it turns out this is actually a real thing and we should pay attention to it,” said Leavitt, an expert in organizational behavior and management and first author of the paper.

“Maintaining a healthy relationship that includes a healthy sex life will help employees stay happy and engaged in their work, which benefits the employees and the organizations they work for.”

Starting off on the right foot

Intercourse triggers the release of neurotransmitter dopamine, which is associated with the brain’s reward pathway, as well as neuropeptide ocytocine, which promotes social bonding and feelings of attachment. It’s a winner combo, which makes sex a natural and pretty fail-proof way of improving your mood. And best of all, the effects of these chemicals can extend well into the next day, the team explains.

To reach this conclusion, the researchers monitored with 159 married employees over a period of two weeks, asking them to complete two short surveys every day. They found that people who had sex reported more positive moods overall the next day — and an improved emotional state in the morning correlated strongly to more self-reported work engagement and job satisfaction throughout the workday.

The effect typically lasted for at least 24 hours, was equally powerful in both men and women, and was significant even after the team corrected for general satisfaction with the relationship and sleep quality — both very powerful ingredients of overall mood.

Image credits Sasin Tipchai.

Leavitt and his team also showed that bringing your work stress to home from work has a negative effect on your romantic endeavors. Employees that failed to disconnect work from their personal life were more likely to sacrifice sex, causing their engagement in work to decline over time. In a society where virtually everyone has a smartphone and after-hours responses to work emails are often expected, these findings underscore the importance of leaving work at the office, Leavitt said.

With this in mind, it may be time to rethink how our work and personal lives fit together, Leavitt says.

“This is a reminder that sex has social, emotional and physiological benefits, and it’s important to make it a priority,” he added. “Making a more intentional effort to maintain a healthy sex life should be considered an issue of human sustainability, and as a result, a potential career advantage.”

“Technology offers a temptation to stay plugged in, but it’s probably better to unplug if you can. And employers should encourage their employees to completely disengage from work after hours.”

Still, I’d give it some time before putting it down on my CV. Let the findings penetrate the job market a bit more, as it were.

“Just make time for it,” he concludes.

Well, it wouldn’t be right to argue with science, would it? Guess we just have to. For productivity’s sake.

The full paper “From the Bedroom to the Office: Workplace Spillover Effects of Sexual Activity at Home” has been published in the Journal of Management.

 

 

Condomless, reversible male contraceptive treatment shows its worth in rhesus monkey trial

Recent success in a rhesus monkey trial might propel a new type of reversible, condom-free male contraceptive closer to market.

Image credits Astryd_MAD / Pixabay.

We have sex for many reasons — mainly because it’s awesome. But for the most part, the biological incentive, that of procreation, isn’t one of them. Coming up with effective contraceptives that don’t take away from the act’s enjoyment can thus have a huge impact on the quality of life for countless people. A new male contraceptive treatment shows great promise in this regard. It has shown its effectiveness in a new trial, successfully blocking reproduction in a group of rhesus monkeys for more than a year.

Known as Vasalgel, the treatment works by blocking the vas deferens — the tubes that sperm travels down through on its merry way. It forms a flexible, spongy, hydrogel material which allows fluids to pass but holds back sperm cells like a net. In theory, this will allow males to ejaculate but eliminates the risk of unwanted pregnancies altogether.

It’s also very simple to administer — all you need to do is get one injection with long lasting effects. Animal studies so far have also shown that the effects are fully reversible.

Monkey business

The trial took place with 16 male adult rhesus monkeys who received Vasalgel injections. They were then housed for a full breeding season with three to nine fertile females. This was done in a free-living environment to ensure a free, unrestricted interaction between the sexes. Seven of the males were housed with the females for up to two years.

During this time, none of the group’s couplings resulted in pregnancy. The monkeys didn’t show any complications or adverse reactions to the treatment. Based on this trial and previous results from rabbit trials, non-profit Parsemus Foundation is now preparing for the first human trials of the treatment. The company said last year that it hopes to have the treatment commercially available by 2018 with an international pricing structure to ensure that men the world over can afford the contraceptive.

It’s an ambitious goal but with the recent success, it probably still holds strong.

“Contraceptive development is a hugely expensive project,” said Parsemus executive director Elaine Lissner last year.

“But this is not just another early-stage lead; we’re so close on this one. It’s time to finish the job we’ve started.”

Vasalgel was inspired by the work on a polymer contraceptive called RISUG, which is in advanced clinical trials in India; some of the men have been using RISUG for more than 15 years. But right now, only local men near the study sites in India are eligible for the trials, and formal reversibility studies have only been done in animals, not men.

If you’re a guy, you’re pretty limited in the range of contraceptives you can use. Despite huge interest from pharmaceutical companies, this market has remained impressively unchanged in the last century. There are several projects in the works — but most rely on chemical or hormonal regulation of sperm production and still come with a wide range of side effects. So the only established contraceptives are condoms, and vasectomies. The first one isn’t guaranteed to work, the CDC estimating a failure rate of 12%. Vasectomies, on the other hand, are very difficult to revert, which understandably puts a lot of people off.

Vasalgel could make a welcomed addition to the market. By physically blocking sperm, it works similar to a condom. However, you don’t have to keep one handy at all times or put anything on before sex. You also don’t have to unpack and risk damaging it, improving ease of use and reliability. We don’t know exactly how long the gel will last in human users, but that’s something Parsemus has to find out in human trials.

Another huge advantage is that the procedure is reversible. According to Parsemus, the rabbit trials have shown that after Vasalgel was flushed from the critters’ vas deferens, sperm production returned to normal. This removes one of the biggest gripes we have with vasectomies — their permanence.

There still is a lot of work to be done before Vasalgel will come to market, however. The rhesus monkey trial was limited in scope and didn’t include a control group. While unlikely that none of the 16 males managed to charm the females, the results should be taken with a grain of salt. It’s a very good result for Vasalgel, but it’s not a definitive answer.

It’s also worth noting that just because something works in animal studies, it’s not a guarantee that human subjects would see the same results. At least three rounds of human trials are needed before it’s even considered for regulatory approval. But up to now the results are encouraging, so there’s a big chance it will ultimately be green-lighted for human use.

The full paper “The contraceptive efficacy of intravas injection of Vasalgel™ for adult male rhesus monkeys” will be published later this week in the journal Basic and Clinical Andrology.

Sex is painful for 1 in 13 women, but no one wants to talk about it

A survey of 7,000 sexually active women aged 16 to 74 found that sex is painful for a lot of women — they just don’t like to talk about it.

Image in Creative Commons.

The study published in BJOG: An International Journal of Obstetrics and Gynaecology, suggests that the problem is much more common than we thought. Medically, the condition is called dyspareunia and its symptoms and manifestations vary greatly. The pain can come either from the external surface of the genitalia or deeper in the pelvis upon deep pressure against the cervix. The pain can be localized or generalized and more or less intense. But no matter how dyspareunia manifests itself, all women suffering from it have one thing in common: they don’t like to talk about it.

Doctors say treatments are available but this is a complex issue with many potential causes. Basically, the underlying cause is not always physical — sometimes it’s psychological or social, and that’s harder to deal with, but still possible. Yet women still treat it as taboo and would rather avoid sexual intercourse than speaking to their doctors about this.

Of those who reported painful sex (7.5%), most were in their late 50s and early 60s but after that, the most common category was women aged 16-24. Lead researcher, Dr Kirstin Mitchell, from LSHTM and the University of Glasgow, explains:

“In younger women, it might be that they are starting out in their sexual lives and they are going along with things that their partner wants but they are not particularly aroused by. Or they might be feeling tense because they are new to sex and they are not feeling 100% comfortable with their partner.”

The thing is that most problems, even minor ones, can easily evolve into something bigger, whether it affects their health or their lifestyle. Sex may be taboo, but it’s a significant part of our lives and it shouldn’t be something to easily give up on. This is why it’s important to talk to your doctor if such a problem emerges. Don’t take advice from the internet (as ironic as it is for me to write this here), just talk to your doctor and try to find a solution. Researchers conclude:

“Many women reporting painful sex also reported another sexual function problem: 62.0% reported lack of interest in sex (compared with 31.9% of women with no pain), 45.2% reported vaginal dryness (compared with 10.4%), 40.2% reported difficulty reaching climax (compared with 14.4%), and 40.1% reported lacking enjoyment (compared with 9.9%). Painful sex was strongly associated with all the sexual function problems we measured, and in particular, with vaginal dryness, feeling anxious during sex and lacking enjoyment in sex.”

Journal Reference: KR Mitchel et al. Painful sex (dyspareunia) in women: prevalence and associated factors in a British population probability survey. DOI: 10.1111/1471-0528.14518

Chimps, unlike humans, are more likely to choose genetically-dissimilar mates

A new study found that while chimps sleep around a lot, they’re pretty selective about who they make little chimps with. The team found that these primates are more likely to conceive with the individuals that most differ from them genetically.

Image credits Pascal Renet / Pexels.

A couple of days ago we’ve talked about how humans tend to pick their mates after similarities in genome — a practice called assortative mating. From a biological point of view, it gives couples a higher chance of passing on desirable traits to their offspring, such as height, intelligence, and so on. It does, however, also come with potential drawbacks.

So let’s take a look at the opposite mating strategy — negative assortative mating. Postdoc associate in evolutionary anthropology Kara Walker and her team at Duke University found that chimps, our closest living relatives, are more likely to reproduce with genetically-different mates.

They took DNA samples from roughly 150 adult chimps from the Gombe National Park in Tanzania, and examine between 8 to 11 variable sites in their genome. They used this data to estimate the genetic similarity between every possible pairing of mates.

Getting some strange

Chimps get down a lot. But their adventures don’t always lead to offspring. The team compared the pairings that produced infants to those that didn’t, and found that females conceived with males that were genetically less similar to them than the average male. They were somehow able to determine genetic similarity among unfamiliar mates who were far removed from them in the family tree, the team concluded.

The female chimps of Gombe NP usually leave their family group when they reach adolescence, seeking a new group (with new males) to reproduce with. These females, even though they had few or no male relatives in the community they immigrated to, showed an even stronger preference for genetically-dissimilar mates than the native females. The researchers say that the females’ mate choices are driven by inbreeding depression — which is the drawback I was referring to earlier.

When two genetically-similar individuals have offspring, they have a higher chance of passing on beneficial genes — but they also have a higher chance of passing on harmful one. In the absence of another gene version to override it, this harmful gene will become active. Over time, the process increases whole populations’ vulnerability to certain pathogens or environmental factors. That is inbreeding depression in a nutshell — a whole group sharing one or more Achilles’s heel because everyone is related to everyone else.

Gene-dar on the ready

Instinctually, this is what makes you and chimps not cool with parent-offspring or sibling-sibling pairing. Such pairings are rare in chimps, and when it occurs it’s less likely to produce individuals that survive to maturity than their peers.

However, while we can determine the genetic makeup of our mate through DNA tests (you should probably not suggest that on your first date), chimps can’t. The researchers are now trying to find out how the chimps can recognize genetically-distant mates. They suggest that the primates do more than simply avoid potential mates they grew up with, being able to distinguish even among unfamiliar partners. It’s not sure yet exactly how they discriminate but it might be a best guess based on appearance, smell, or sound, said professor of evolutionary anthropology at Duke and senior author of the paper Anne Pusey.

Timing could also play a factor. The females might be pickier about partners during their most fertile period. The team is also considering processes that take place after mating, such as a female unconsciously choosing some males’ sperm over others or influencing the outcome of a pregnancy, Walker said.

The full paper “Chimpanzees breed with genetically dissimilar mates” has been published in the journal Royal Society Open Science.

 

We pick our mates by their genome — even if we aren’t aware of it

A new study found that we’re much more likely to choose mates that are similar to us — because we seek them out. These mating preferences are statistically relevant and play a part in shaping the human genome, the authors conclude.

Image credits Pascal Renet / Pexels.

A team from the University of Queensland, Australia, says that you’ll likely marry someone a lot like you. Someone who has a similar height, body weight, someone of similar intelligence. And it doesn’t happen because birds of a feather get together, as the saying goes — it happens because we actively search for mates with a genetic load-out similar to our own.

Gene-mates

The team worked with databases of people’s physical and genetic traits. They selected more than 24,000 married couples of European ancestry. For each couple, they selected one partner and isolated the genetic markers for traits including height and body mass index (BMI). Using this data, they then tried to predict the same characteristic in their partner. If one person’s genetic material suggested he was tall, for example, their partner was predicted to also be tall. The goal was to find correlations in these traits. So the final step was to compare these predicted characteristics against their actual value.

The team found a strong statistical correlation between one person’s genetic markers for height and the real height of their partner. They also identified a weaker but still statistically significant correlation between the genes governing BMI and the real BMI of their partners. The correlation is much stronger than what you’d expect to see in the case of random mating. These findings are evidence that people actively seek partners with a genetic makeup similar to their own, the team reports.

Picking mates based on similar traits is a pattern of sexual selection known as assortative mating. It allows individuals to pass traits to their offspring. In effect, this practice increases relatedness in family groups and helps offspring survive better — provided the trait is beneficial in their environment. It has previously been observed in animal populations: brightly colored eastern bluebirds mate with each other while bluebirds duller in color pair up among themselves, for example.

The team also found evidence of assortative mating for other traits in 7780 couples in a U.K. database. They report a “remarkably high correlation” for genetic markers linked to years of education. While it’s unlikely people chose their mates based on actual years spent in school, it does imply that they select for similar interests — which are often associated with levels of education, says team member Matthew Robinson, a postdoc in the lab of geneticist Peter Visscher at the University of Queensland in Brisbane.

Assortative mating “affects the genomic architecture of traits in humans,” Robinson added. As such, the findings are useful in establishing more accurate genetic models, which predict how likely it is that members of a family will inherit diseases or physical traits.

Robinson now plans to use the method to “understand why spouses are similar on many other, behavioral traits, such as IQ, political preference […] and psychiatric disorders.”

The full paper “Genetic evidence of assortative mating in humans” was published in the journal Science Human Behavior.

Why do people have sex?

Sex — we do it for the kids.

Or do we? Human sexuality is a complex thing, which both defines and is defined by each and every one of us. An integral part of the human experience, we all hope to one day dip our toe (and other parts) into it. Understanding sexuality therefore is both a scientific and a deeply personal topic.

Sorry to intrude, ladies.
Image credits Michael Schwarzenberger / Pixabay.

You reading this now is only possible due to one simple fact — half of your ancestors, without fail, have successfully had sex with the rest of your ancestors. Which, generally speaking, is why animals have sex.

But if they were witty, pretty, or lucky enough, some of them likely became acquainted with the genitals of other people too, without tying your bloodlines together. Which begs the question: why do people have sex?

The physical sex

I may be shooting for the Captain Obvious prize here, but sex feels good and is a key catalyst for baby-making. These two properties go hand in hand. Sex is necessary for the continuation of your genes and the human race — therefore, you’re rewarded for having sex (pleasure) so you’ll seek it out more.

Humans today have turned this biological incentive on its head. Thanks to a sleuth of traditional and recent birth control options, most of the sex that goes on right now isn’t about procreation. People start having sex long before they plan on having children and continue to do so long after they’ve had them. Long after they’ve had them. The chance of pregnancy, to a degree, limits the pleasure many people derive from their sex lives, or may even impair it altogether.

We also do a lot of things between the sheets (and in front of screens) that have absolutely nothing to do with making babies and absolutely everything with getting off. The fact that porn, masturbation, oral sex and so on exist, contravenes the assumption that human sexuality is centered around procreation. We assign sexual meaning to body parts, objects, or actions that are not part of the sexual process — shoulders, six-packs, high heels, spanking, hair pulling.

Eroticism, sexuality, and procreation have, to an extent, been decoupled in recent times — and while opinions may differ on this, procreation is no longer in the limelight.

The emotional sex

Being horny and seeking sexual release are definitely good reasons to have sex. But if you really think about it, there’s a much simpler and faster method on hand to take the edge off. And you don’t even have to leave the house.

Some people just peel carrots. Others preffer to be tied and gagged when doing it.
Image credits congerdesign / Pixabay.

Most people who are or have been in a relationship can remember one time when they weren’t really feeling it, but did the deed anyway. Maybe you were tired or had to power through a headache but your significant other was all fired up so you took (gave?) one for the team.

We’ve also established that sex is fun. But there’s something that makes it different from other fun stuff, isn’t there? Drinking or playing video games is also fun, but we can do that with whomever, whenever, and no one will feel hurt. Hopefully.

So physical pleasure is not all that’s involved here. According to a study by Cindy Messon and David Buss published in 2007 in PubMed, it’s just one of at least 237 reasons why people initiate or consent to sex. The most and least usual, according to US college students, are the following:

    1. I was attracted to the person.
    2. It feels good.
    3. I wanted to experience the physical pleasure.
    4. I wanted to show my affection to the person.
    5. I was sexually aroused and wanted the release.
    [……]
    233. I wanted to give someone else a sexually transmitted disease (seriously?).
    234. The person offered to give me drugs for doing it.
    235. I wanted a raise.
    236. I wanted to breakup my relationship.
    237. It was an initiation rite to a club or organization.

You can see the full list of questions published by BusinessInsider here.

And just in case you missed the cue, now’s the time to remind you — keep the broadband well protected when connecting to the network. Especially if either is public.
Image via Meditations / Pixabay.

Keep in mind that the results were based on the responses of college students — so they’re likely biased towards short-term physical gain. “Attraction” is a foggy term to use, as it could be interpreted solely as physical attraction, emotional attraction, or a mix of both. Still, the emotional component strikes on both the high end (nr.4) and the low one (nr.236) of the list.

Sexual pleasure is also highly dependent on your emotional state and mood. A touch that would send a shiver down your spine with one partner can easily send chills if done clumsily — or if it’s not consensual. So it’s not all up to you. Getting quality sexy time requires a lot of external factors falling into place.

Which drives us to the last point.

The social sex

Humans are, perhaps more so than any other animal, social beings. Our sexuality is closely intertwined with our social lives. By definition, you have to interact with another person to have sex. So by definition, sex has a social component — while still being deeply personal, as we’ve so far seen.

A quote you may recognize from House of Cards but was actually produced by Oscar Wilde says that ‘everything is about sex except sex — sex is about power’. It can be used as a show of dominance, as a display of power. Both sexes enjoy engaging in power plays, either traditionally or going against traditional sex roles.

Sex is also closely regulated by social forces. Sexual shaming, minority gender stigma, and felt stigma are all ways socially-accepted ideals are forced upon the individual. Deviation from what is considered normal at the time is also usually punished in society. Sometimes with a very heavy hand: For much of the US’ history, some people could not legally have sex or marry the people they were attracted to. Just imagine that — being told that your arousal is illegal. I can’t even begin to understand how that feels like.

These guys and gals know, though.
Image credits naeimasgary / Pixabay.

American sociologist Randall Collins has long argued that sex is, you’ll never guess, a social construct. Just like many other “rituals“, it can only be understood from a social point of view. Water cooler conversations, Sunday’s church, or a date are all social rituals, he says. They’re different in purpose but follow the same social rules and are all based on the same psychological processes. Each one serves to gather people in a group aware of all its members who have a common point of interest and share an emotional connection.

He goes on to say that all interaction rituals have the same effects. Solidarity increases between the participants — ‘we’re one team’ for sports fans, ‘we’re faithful to each other’ in a couple. Mental energy builds up — ‘I am in love’. By repeating the ritual, a memory will come to symbolize the relationship to the partners — ‘that one romantic getaway in Hawaii’. An object will become ‘sacred’, such as a wedding ring for example. And certain gestures will come to belong to the group — ‘only we can do that with each other’. In the end, the ritual comes to clearly delineate the group, ‘us’, from the rest of humanity, ‘them’.

Why we have sex

So to recap: we have a bit of sex to procreate. We have a lot of sex because it feels good — because it’s pleasurable, or because it will give someone dear pleasure. We do it because we’re lonely, or horny, or drunk. We do it to show our feelings, we do it to break up, and for some ungodly reason, some people do it to spread STDs around.

We have sex because we want to move ahead in society. To become popular, to gain station, or the arm, ear (and other bits) of someone powerful. Sometimes we do it out in the open, and sometimes we have to hide in the shadows to be ourselves.

In the end, we have sex because we’re humans — and humans have sex.