Genetic analysis of orgasmic function in twins and siblings does not support the by-product theory of female orgasm

Thanks to Alex C for the link

Zietsch BP, Santtila P(2011)Genetic analysis of orgasmic function in twins and siblings does not support the by-product theory of female orgasm. Animal Behaviour. 82(5): 1097-1101 doi:10.1016/j.anbehav.2011.08.002

Abstract
The evolutionary basis of human female orgasm has been subject to furious scientific debate, which has recently intensified. Many adaptive explanations have been proposed, invoking functions from pair bonding and mate selection to sucking up sperm, but these have been attacked as being based on flawed logic and/or evidence. The popular alternative theory is that female orgasm is not adaptive and is only evolutionarily maintained as a by-product of ongoing selection on the male orgasm–ejaculation system. This theory has not been adequately tested. We tested one of its central tenets: that selection pressure on the male orgasm is partially transmitted to the female via a positive cross-sex correlation in orgasmic function (susceptibility to orgasm in response to sexual stimulation). Using questionnaire data from over 10 000 Finnish twins and siblings, we found significant genetic variation in both male and female orgasmic function, but no significant correlation between opposite-sex twins and siblings. This suggests that different genetic factors underlie male and female orgasmic function and that selection pressures on male orgasmic function do not act substantively on female orgasmic function. These results challenge the by-product theory of female orgasm.

Highlights
► Orgasmic function is heritable in both men and women.
► Opposite-sex twins and siblings do not correlate in their orgasmic function.
► Suggests different genetic factors underlie male and female orgasmic function.
► Selection pressure on male orgasmic function cannot act on female orgasmic function.
► Challenges the theory that female orgasm is a simply a by-product of the male orgasm.

*updated* Hysteria trailer

a cheeky movie about a key moment in the study of human sexuality



*updated*

a few more interesting things came out today in case you are interested in female sexuality

a TEDx talk on female orgasm


and a documentary on Persistent Sexual Arousal Syndrome (which can be found at TOP DOCUMENTARY FILMS)

What came first? the empathy or the orgasm

This is a terrifically written pop science article, one of the best writes up I have ever read. The topic is beyond intriguing and the study has a really great sample size and an elegant research design (for a human study of this kind). It also reminded me of the article "Empathy is what really sets vegetarians apart". So clearly this proves that vegetarians make better lovers ;) - MA

BY CORY SILVERBERG
Does Empathy Make Us Orgasmic or Do Orgasms Give Us Empathy?
from about.com

A paper published this month in the Journal of Adolescent Health turns our attention to a much under researched area of sexual health; pleasure. Specifically the authors, Adena Galinsky and Freya Sonenstein from the Johns Hopkins Bloomberg School of Public Health used data collected by the National Longitudinal Study of Adolescent Health, and examined associations between individual reporting on sexual pleasure and self-reports of autonomy, self-esteem, and empathy.

The researchers point out that despite a growing acceptance of the idea that sexual pleasure is a key aspect of sexual health (and that sexual health doesn't mean simply an absence of disease or unintended pregnancy), science hasn't contributed much in the way of data on the relationship between feeling sexual pleasure and experiencing overall sexual, or general, health.

Here sexual pleasure was measured by three questions:

1. When you and your partner have sexual relations, how often do you have an orgasm? (answer options were: most of the time, more than half the time, about half the time, less than half the time, hardly ever)
2. How much do you like for your partner to perform oral sex on you? (answer options were: like very much, like somewhat, neither like nor dislike, dislike somewhat, dislike very much)
3. How much do you like to perform oral sex on your partner? (same as above)

Autonomy, self-esteem, and empathy were measured by having participants respond to statements such as "I defend my own beliefs, I am independent, I am willing to take a stand, and I am assertive." and "I am sympathetic, I am sensitive to the needs of others, I am understanding, and I am compassionate" indicated how true each is for them.

The researchers then examined the relationship between orgasm frequency/enjoyment with oral sex and the extent to which participants scored high or low on self-esteem, empathy, and autonomy.

Findings on Sexual Pleasure
There were 3,237 people (60% were women, almost three quarters were white, mean age was 22) all of whom had been in a sexual relationship with an opposite gender partner for at least three months.

The good news is that the majority of all respondents seem to be enjoying sex more than half of the time they are having it. While gender differences in this kind of research always need to be taken with a truckload of salt, it may be worth noting the discrepancy in regularity of orgasm. 87% of men reported orgasm most or all of the time and 47% of women reporting it most of the time.

Perhaps a less expected discrepancy was found in responses to who enjoys performing oral sex. 61% of men as opposed to 37% of women, reported enjoying performing oral sex most or all of the time.

Sexual Pleasure, Autonomy, Self-Esteem, and Empathy
When they compared people's responses statements about autonomy, and their enjoyment of sex, they continued to find gender differences. While regarding oneself as autonomous was connected for men to regularity of orgasm, it wasn't connected to enjoyment performing or receiving oral sex. For women it was connected to all three (although a weaker connection was found with the oral sex measurements than with the orgasm measurement).

Turning to self-esteem, for men it was only related to enjoyment of performing oral sex (that is men who rated self-esteem higher were more likely to enjoy performing oral sex). For women self-esteem was related to all three measures of sexual enjoyment, the strongest relationship was to enjoyment of performing oral sex (again, higher self-esteem rating, more likely to enjoy performing oral sex.

The one consistent finding for all participants was with empathy. For all participants empathy was significantly related to all measures of sexual enjoyment, although not equally, as empathy was more strongly associated with regularity of orgasm than with liking giving or receiving oral sex. Nonetheless, this finding held to varying degrees across all groups of participants.

Enough With the Numbers, How Can I Be Better in Bed?
Unfortunately pretty much all the news and bloggy coverage of the study has traded in basic science for a catchy headline. This study does not tell us that being more empathetic makes you a better lover or even enjoy sex more. The research can't know the direction of the correlation found, so it's impossible to know which came first, the empathy or the orgasm.

While most of the headlines proclaim that being an empathic person makes you a better lover, it's just as likely that the more orgasms you have, the more empathetic you become. Maybe it's the experience of being with someone experiencing intense pleasure, pleasure that you presumably had a hand (or some other body part in) that builds up your self-esteem or empathy. It's possible that being autonomous makes orgasms come easier because we're able to focus on our own pleasure and not the pleasure of the other. Maybe the more oral sex I perform on someone, the higher my self-esteem goes.

This research is exciting not because it delivers any sex tips or provides the foundation for another sex manual, it's exciting because of the questions it asks, and the directions the findings suggest for future research. Why, for example, does it seem that rating yourself high on self-esteem is more connected to enjoyment performing oral sex than receiving oral sex? What goes into us being able to enjoy receiving oral sex anyway? If you think it's all about anatomy and response, how come there's such variation?

As the authors themselves state, this study is just the beginning. Lucky for us, it's a clearly written and fairly presented beginning, which hopefully will inspire more research not just on this topic, but of this caliber.

Read more - HealthDay: Self-Confidence, Empathy May Make for Better Sex

Citation: Galinsky, A.M. & Sonenstein, F.L. (2011) The Association Between Developmental Assets and Sexual Enjoyment Among Emerging Adults. Journal of Adolescent Health 48: 610-615.

Abstract
Purpose
To examine the associations between three key developmental assets and an aspect of sexual health, sexual enjoyment, which has rarely been studied in young adults, although its importance is stressed in all recent sexual health policy statements.

Methods
Using data from wave III (2001–2002) of the National Longitudinal Study of Adolescent Health, and multiple logistic and ordered logistic regression, we explored the associations between sexual pleasure and autonomy, self-esteem, and empathy among 3,237 respondents aged 18–26 years in heterosexual relationships of ≥3-month duration. We also examined the distribution of sexual pleasure across various socio-demographic groups.

Results
Compared with young women, young men reported more regular orgasms and more enjoyment of two kinds of partnered sexual behavior. Sexual enjoyment was not associated with age, race/ethnicity, or socioeconomic status. Among women, autonomy, self-esteem, and empathy co-varied positively with all three sexual enjoyment measures. Among men, all associations were in the same direction, but not all were statistically significant.

Conclusion
A substantial gender difference in enjoyment of partnered sexual behavior exists among emerging adults in the United States. This study is the first to use a representative population sample to find a relationship between developmental assets and a positive aspect of sexual health − sexual pleasure.

AWESOME: Women's orgasms leave them temporarily impervious to pain

Thanks to Cory R for the link! PS: yay for the ladies!
From Perth Now & the Australian
Female orgasm 'overwhelms'

THE brain's reward circuits and rational thought processes are overwhelmed with electrical activity when a woman reaches sexual climax. In the first film of what goes on inside a woman's brain as she approaches and then experiences orgasm, researchers recorded how sexual arousal generates a cascade of events that, at its peak, involves 30 parts of the brain. A woman not only experiences longer and deeper orgasms than a man, but they so overwhelm her nervous system that they leave her temporarily impervious to pain, the film shows.

"In women, orgasm produces a very extensive response across the brain and body," said Barry Komisaruk, professor of psychology at Rutgers University in New Jersey, who oversaw the research. Professor Komisaruk and his colleagues plan to show their film this month at Neuroscience 2010, a conference organised by the US Society for Neuroscience.

In their research they asked 16 women to "self-stimulate" until they achieved orgasm, while lying under a blanket in a functional magnetic resonance imaging scanner. Despite the clinical surroundings, all the women were able to achieve their goal, mostly in less than five minutes -- although some took up to 20. The scientists used the machine to observe which parts of the brain became active at each phase. The film, based on images taken of the women's brains every two seconds, shows the surges in electrical activity as an orgasm overwhelms different combinations of brain areas in turn. They flood not only the brain's "reward circuits" but also the parts associated with rational thought.

The pattern of activation seemed to be similar in all the women observed. This could help researchers establish a picture of what a normal orgasm looks like -- and possibly help those suffering from sexual dysfunction. About one woman in seven never experiences an orgasm.

Other researchers have studied what happens in men's brains during orgasm. One study at the University of Groningen in The Netherlands showed "extraordinary activation of the ventral tegmental area", another part of the brain's reward circuitry. The early evidence suggests this effect, while similar in nature, is shorter-lived and not as strong as the sensation experienced by most women.

"In one experiment we asked women to self-stimulate and then raise their hands each time they orgasmed. Some women raised their hands several times each session, often just a few seconds apart," Professor Komisaruk said. "So the evidence is that woman tend to have longer orgasms and can experience several of them."

British scientists deny existence of Gspot - world pities British women...

from The Guardian.co.uk
French hit back after British attack on G-spot touches nerve
by Lizzy Davies
After scientists in London declared the G-spot may be a myth, gynaecologists gather in Paris to launch counterattack

There are a handful of subjects - among them cricket, the weather and the art of downing pints through a funnel - on which the French deign to allow the English a degree of authority. Sex, however, is not one of them.

Today, just three weeks after scientists at King's College London declared that the elusive G-spot may be a myth, a group of gynaecologists gathered in Paris to launch a counter-attack on what they called a "totalitarian" approach to female sexuality.

Denouncing the study carried out last year by British researchers as fundamentally flawed, the French scientists insisted the fabled erogenous zone did exist in many women – around 60% according to Sylvain Mimoun, the organiser of the conference.

But, they said, it had fallen victim to an Anglo-Saxon tendency to reduce the mysteries of sexuality to absolutes. This attempt to set clear parameters on something variable and ambiguous, they said, was characteristic of British scientific attitudes to sex.

"The King's College study ... shows a lack of respect for what women say," said Pierre Foldès, a leading French surgeon. "The conclusions were completely erroneous because they were based solely on genetic observations and it is clear that in female sexuality there is a variability ... It cannot be reduced to a 'yes' or 'no', or an 'on' or an 'off'."

The British study – the largest ever carried out on the body part that bears the initial of its discoverer, German gynaecologist Ernst Gräfenberg – involved 1,800 female twins being asked whether or not they thought they had a G-spot. Researchers concluded earlier this month that there was no proof to suggest it existed.

Odile Buisson, a gynaecologist, said the study was a demonstration of a cultural difference in attitudes to sex, with Gallic acceptance of ambiguity sitting uneasily beside an Anglo-Saxon need to explain everything. "I don't want to stigmatise at all but I think the Protestant, liberal, Anglo-Saxon character means you are very pragmatic. There has to be a cause for everything, a gene for everything," she said, adding: "I think it's totalitarian."

Foldès, who pioneered a globally renowned technique to restore the clitorises to women who have been circumcised, said the questions in the King's College study started from the false premise that all G-spots are alike. In fact, he says, the highly sensitive area bears little resemblance to the famed magic button guaranteed to generate immediate pleasure.

Moreover, said Mimoun, it will only be felt by a woman who knows it is there and takes steps to cultivate it. "In discovering the sensitive parts of her own body, this sensitive zone [the G-spot] will become more and more functional," he said "But if she has never touched it and no one else has ever touched it ... it won't exist for her as a consequence."

Thanks to Andrew F. for the link!
I think Wayne Marshall would have much to say about this outrage:

Fellatio by Fruit Bats Prolongs Copulation Time

Tan M, Jones G, Zhu G, Ye J, Hong T, et al. 2009 Fellatio by Fruit Bats Prolongs Copulation Time. PLoS ONE 4(10): e7595. doi:10.1371

Abstract

Oral sex is widely used in human foreplay, but rarely documented in other animals. Fellatio has been recorded in bonobos Pan paniscus, but even then functions largely as play behaviour among juvenile males. The short-nosed fruit bat Cynopterus sphinx exhibits resource defence polygyny and one sexually active male often roosts with groups of females in tents made from leaves. Female bats often lick their mate's penis during dorsoventral copulation. The female lowers her head to lick the shaft or the base of the male's penis but does not lick the glans penis which has already penetrated the vagina. Males never withdrew their penis when it was licked by the mating partner. A positive relationship exists between the length of time that the female licked the male's penis during copulation and the duration of copulation. Furthermore, mating pairs spent significantly more time in copulation if the female licked her mate's penis than if fellatio was absent. Males also show postcopulatory genital grooming after intromission. At present, we do not know why genital licking occurs, and we present four non-mutually exclusive hypotheses that may explain the function of fellatio in C. sphinx.

from the discussion

We speculate that the female C. sphinx licks the male penis to increase penile stimulation, stiffening the penis and maintaining the male's erection. At the same time, the female's saliva may increase lubrication, thus facilitating intromission and thrusting. In combination, these features may prolong copulation in C. sphinx.

So in a similar way to the anthropoid primates, the C. sphinx females (like most animals) are not passive during copulation but rather communicate with the male, in this case by licking his penis. We propose a series of adaptive hypotheses to explain genital licking in C. sphinx. First, genital licking may lubricate the penis or increase penile stimulation, prolonging the duration of copulation. Prolonged copulation might assist sperm transport from the vagina to the oviduct, or stimulate secretions of the pituitary gland in the female and hence increase the likelihood of fertilization. Second, prolonged copulation might be a method of mate-guarding, because the mates would normally segregate after copulation to form unisexual groups which persist throughout the non-breeding season. Third, fellatio may confer bactericidal benefits and assist in the prevention of sexually transmitted diseases (STDs) both to females, and to males that lick their own penis briefly after copulation. Saliva has a protective repertoire that goes beyond antibacterial activity to include antifungal, antichlamydial, and antiviral properties as well. Finally, genital licking may facilitate the detection and identification of MHC-dependent chemical cues associated with mate choice.

Thanks to Dieter L. for the link

Six things science has revealed about the female orgasm

From the New Scientist
17:35 28 May 2009 by Michael Marshall

This week we report on the continuing debate about female ejaculation: is it real, and if so why does it happen?
See Everything you always wanted to know about female ejaculation (but were afraid to ask)
Ejaculation is just one of the aspects of female sexuality that are being demystified by research. In particular, the female orgasm, the subject of so many myths and folk beliefs, is gradually being understood.
Following some intense field research, here are some of the key facts about the female orgasm, as revealed by modern science.

1) The G spot is real
The G spot is a small region in the vagina that, if stimulated, can produce wildly intense orgasms – or so the popular claim goes. However, for decades, strong evidence for the region's existence was harder to find than the spot itself.
However, in 2008, an Italian research team found anatomical differences between women who could have G-spot orgasms and women who couldn't; apparently solving the mystery. The researchers have since begun teaching women with G spots how to put them to use.
See Ultrasound nails location of the elusive G spot

2) The brain switches off
It's folk wisdom that people can't think straight when they have sex on their minds, but when women have an orgasm most of their brains switch off.
A brain scanning study showed that many areas of women's brains were deactivated during orgasm, including those involved in emotion. The effect was less striking in men, but that may be because male orgasms are so short they are hard to detect in a brain scan.
See Orgasms: A real turn-off for women

3)Many women can't have orgasms
According to a 1999 survey, around 43 per cent of women in the US have some sort of problem with their sex lives (Journal of the American Medical Association, vol 281, page 537).
Female sexual dysfunction (FSD) is so common that the very idea that it is a medical disorder has come under attack. If nearly half the female population has a problem, say critics, does that mean it is our society that is dysfunctional?
Even so, efforts to develop drugs to treat it are underway. The impotence drug Viagra has had mixed results in women, but there are many other avenues being explored.
See What women want

4) Genes affect orgasm frequency
According to the first genetic study of the female orgasm, up to 45 per cent of the variation in women's ability to have them could be down to genes.
Many women never have orgasms during intercourse, and some also cannot have them through masturbation. Some of this may be down to external factors like upbringing, but the study showed the genetic factor is significant.
See Genes blamed for fickle female orgasm

5)Technology can help
Perhaps the most extreme solution is the so-called "orgasmatron"; an implant inserted into the spinal cord, which stimulates the user when switched on via a remote control.
Despite an initial struggle to find subjects for clinical testing, the device is now in development.
See Push my button

6) Some mystery remains
The female orgasm is a puzzle for evolutionary biologists. It is unclear why women should have orgasms at all, and it is particularly baffling that so many women should be unable to have orgasms during penetrative sex, but able to have them by masturbation.
According to researcher Elisabeth Lloyd, that implies that female orgasms are an evolutionary accident. Like male nipples, they persist simply because there is no good reason to get rid of them.
See The case of the female orgasm