Everything you know about sex is true.

A person's attitude to sex might be written all over their face, according to a study of attractiveness.

A computer generated image of the face on the right which is of someone who is more likely to be interested in a short-term sexual relationship whilst the one on the left is more likely to be interested in a long-term relationship.

"What was interesting was the strength of the preference among men for women who were interested in short-term sex and the strength of the preference of the women for men not interested in short-term sex," said Lynda Boothroyd of Durham University, who led the study.

Researchers surveyed 700 men and women in their early 20s, who were asked to look at photographs of the opposite sex and judge how attractive they were and what their attitudes to sex might be - such as whether they were interested in long or short-term relationships. The answers were compared with the real-life behaviour and attitudes of the people in the images.

The results showed that men and women could generally judge who would be more interested in a short-term fling just by looking at their expression and features. In one study of 153 participants, 72% of people correctly identified the attitudes from photographs more than half of the time. "Men who said they were interested in short-term sex were seen as looking more masculine," said Boothroyd.

Emmanuele Jannini, of the University of L’Aquila, claims to have found the first anatomical evidence for the existence of the G-spot, the elusive and controversial pleasure point, which some women say triggers powerful vaginal orgasms. His research could also explain why so many women have searched for their G-spot in vain: it suggests that not all of them have one.

The G-spot is named after Ernst Gräfenberg, a German gynaecologist who in 1950 proposed that a sensitive point on the vaginal wall could provoke particularly intense orgasms in some women, which differ from normal orgasms caused by clitoral stimulation. Finding it has since become a staple of good-sex handbooks.

Its existence, however, has been widely questioned. Many women have always found it impossible to locate, leading them to doubt their own sexual skills or that of their partners, or to wonder whether the whole idea of a vaginal pleasure point is a myth.

Dr Jannini has found anatomical differences between women who can have vaginal orgasms and those who cannot and told New Scientist that it may be possible to develop an ultrasound test that can tell women whether they have one.

He used ultrasound to examine nine women who said that they could have vaginal orgasms and eleven who said that they could not. He found that the tissue between the vagina and urethra was thicker in the first group, which could be linked to their ability to have an orgasm.

Image source.

The sexual preferences of fruit flies have been switched from gay to straight and back again with drugs and genetic engineering.

Scientists from the University of Illinois found that a mutation in a gene known as “gender-blind”, or GB, can make flies bisexual, and that manipulating its activity can switch this sexual trait on and off.

The findings would suggest that homosexuality has a clear biological basis, but that this is not necessarily hard-wired by the genes. A combination of genetic and environmental factors seems to be required.

While the research, led by David Featherstone, does not necessarily have direct implications for humans, whose brain and nervous system are far more complex, it does show that changes in biology can directly affect sexual behaviour.

“The GB mutant males treated other males the same way normal males would treat a female,” Dr Featherstone said. “They even attempted copulation.”

Drugs and genetic engineering were then used to manipulate synapse strength independently of the GB gene, with similar results. “I never thought we’d be able to do that sort of thing, because sexual orientation is supposed to be hard-wired,” he said. “This fundamentally changes how we think about this behaviour.”

Researchers in Switzerland and Canada have pinpointed a gene that makes females suck up sperm through their mouths.

Lucky you, there's even a video of the discovery:

The gene was found in the cichlid fish, where the males have evolved a way to lure females close so that they can squirt sperm into their mouths.

As is the case in many fish species, the sight of a brightly coloured male triggers females with ripe eggs to start releasing them. But in cichlids, there is a twist. Females hold their eggs in their mouths and incubate them there after fertilisation.

As soon as a female has spawned her eggs, she collects them up in her mouth. Normally, sperm released into the water by a male nearby will then fertilise the eggs.

But males of certain cichlid species have evolved a way to increase the odds that females take up their sperm. Oval yellow markings resembling the eggs are found on the anal or pelvic fins. When a female approaches the male, she thinks she sees an egg on its fin, so tries to vacuum it up in her mouth – and get a mouthful of sperm from the canny male in the process.

The scientists believe they have identified the gene that makes this bizarre mating behaviour possible.

Viagra may make a man more loving as well as improve his physical performance, research suggests.

Scientists have discovered that the impotence drug can boost levels of a "cuddle chemical" in the brain, promoting romantic feelings and bonding between couples.

Image via kottke.

Apparently if you cannot get your hands on the Gaydar gadget shown below, you might still be able to detect who is homosexual or bisexual, by listening to the way they talk.

In the 1990s, researchers tackled a question that was discussed everywhere except in formal academic settings. When someone's speech "sounds gay", what makes it sound that way? Here are three pioneering studies.

In 1994, Rudolf P Gaudio, of Stanford University, published a paper called Sounding Gay: Pitch Properties in the Speech of Gay and Straight Men. Gaudio studied the speech sounds of (a) some openly gay white American men and (b) some openly straight white American men. Then he asked volunteers to listen and see if they could identify which was which. They could.

In 1996, Jack Avery and Julie Liss produced a study called Acoustic Correlates of Less-Masculine Sounding Speech. The researchers compared recorded samples of two kinds of speech, one they called "less-masculine-sounding (LMS) male speech". The other they termed "more-masculine-sounding (MMS) male speech".

Acoustically, Avery and Liss said, there were "significant differences between measures of fundamental frequency contours, vowel formant midpoint values, and in the first, third and fourth spectral moments of two fricatives".

Nearly a decade later, Janet Pierrehumbert and four colleagues looked at a very particular aspect of the question "What, technically, is the sound of gay male American speech?" They also examined the speech of lesbian and bisexual American women.

The team published a study called The Influence of Sexual Orientation on Vowel Production. One passage sings with clarity:

"Differences in the acoustic characteristics of vowels were found as a function of sexual orientation. Lesbian and bisexual women produced less fronted /u/ and /[open aye]/ vowel sounds than heterosexual women. Gay men produced a more expanded vowel space than heterosexual men. However, the vowels of gay, lesbian, bisexual speakers were not generally shifted toward vowel patterns typical of the opposite sex."

The general topic is still, academically speaking, in its early days. A few other scholars have joined Gaudio, Avery, Liss and Pierrehumbert in doing official, list-it-on-the-resumé research. But mostly, it remains a subject of informal, non-technical study.

Via the f-word. Thanks Marcell!