Picture: Steve Lawrence

As tight-lipped as the average person is about discussing sex, there are loads of rumours about the act – probably stemming from the playground – which seem to have worked their way into the mainstream.

Seeking neither to debunk nor promote, we take a look at some of the most enduring conjecture, scaremongering, ridiculous theorising and (some strangely compelling) ideas about sex.

The G-spot

The mythical G-spot, an erogenous zone in the vagina which, when stimulated, can lead to powerful orgasms, has been a matter of some debate among men and women for the 60 years since German gynaecologist Ernst Gräfenberg hypothesised about it.

However, a recent study of 1 800 British women by King’s College in London has raised serious doubts about its existence.

The research was conducted on pairs of identical twins between 23 and 83 and, because identical twins have the same genes, it was expected to show that if the G-spot existed both sisters would have one. Which it didn’t.

“This is by far the biggest study ever and it shows conclusively that the idea of a G-spot is subjective,” said study co-author and professor of genetic epidemiology Tim Spector.

Masturbation causes blindness

Probably in an attempt to stop teenagers from doing it, some of the scariest sex-related myths have arisen about masturbation. Among the most common are masturbating causes blindness; it will make you grow hairs on the palm of your hands; and it could cause sterility in later life.

All such theories have been debunked by medics but continue to crop up – probably a reflection of the guilt associated with the activity. In 2007 the College of Optometrists took the matter into their own hands by declaring categorically masturbation does not cause visual impairment.

Size matters

Whether a man’s penis size matters to his partner or not, you can bet it matters to him. The average penis size is between five and six inches erect and around three and a half inches flaccid.

An internet survey in 2005 of more than 52 000 men and women revealed that only 55 percent of the male respondents were happy with their penis size, whereas 85 percent of participating women said they were “very satisfied” with their partner’s penis.

Other studies have found that many men who believe their penis size to be inadequate are actually average-sized. Misconceptions derive from the ridiculous (Italian pepper grinder-sized members featured in porn movies) to the unfortunate (the perceptive foreshortening men experience when looking down).

Despite the many penis enlarging pumps, pills and practices promulgated by spam emails and internet advertising, few experts endorse such tools.

Men think about sex every 52 seconds

Every few years scientists come up with an estimate of how often a man thinks about sex. Every three seconds, seven or 52 – they have not yet reached a consensus.

Dr Louann Brizendine’s book The Female Brain claims “studies have shown that while a man will think about sex every 52 seconds, the subject tends to cross women’s minds just once a day”. Ask the average man, however, and he’ll probably scoff at the findings.

But it’s hard to imagine how anyone can negotiate the morning commute, working life and normal human interaction with erotic images popping uninvited into the subconscious every 52 seconds.

Female ejaculation

Female ejaculation is hotly contested by sexologists. In surveys 35 percent to half of women have said they’ve had a so-called “gushing orgasm”.

There are references to the apparent phenomenon in Indian sex tome the Kama Sutra as well as Greek and Roman accounts.

Female ejaculation is also mentioned in early 20th century marriage manuals such as Theodoor Hendrik van de Velde’s Ideal Marriage: Its Physiology and Technique (1926), which says “it appears the majority of laymen believe something is forcibly squirted or expelled from a woman’s body in orgasm, and should happen normally, as in the man’s case. It is just as certain that such an ‘ejaculation’ does not take place in many women of sexually normal functions”.

Women prefer circumcised men

There is huge online debate about whether women prefer penises to be circumcised – an operation, usually conducted in infancy, where the foreskin is cut away. Issues such as whether a man’s penis looks more attractive, gives more satisfaction (to him and his partner) and is more hygienic are under keen discussion.

In Uganda last year 500 women interviewed found their circumcised partners just as satisfactory between the sheets as their uncircumcised counterparts.

A 1999 study by the British Journal of Urology International revealed that men circumcised as adults reported a loss in sensation, but more control in reaching climax.

The numerous studies rarely consider the same data or reach comparable conclusions; so, in the end, it seems to come down to personal taste.

However, as most of the world’s men are uncircumcised many women will never be able to compare.

Women get emotionally attached after sex

“Can a woman have sex like a man?” ponders Sex And The City character Carrie Bradshaw in one of her entertainingly obtuse newspaper columns. She’s asking if women can shake off the assumption that by getting into bed with a man their pink and fluffy minds will whiz off into the realms of marriage and babies.

Sex therapists largely agree that women are more prone than men to depression after casual liaisons. And during orgasm the body releases oxytocin, dubbed the “cuddle hormone”, which is believed to foster post-coital feelings of love and attachment in both sexes. However, a survey by magazine Marie Claire showed a mixed response from women debating the issue.

A third claimed to enjoy casual sex without emotional repercussions, while the rest found their experiences emotionally unfulfilling or sometimes fulfilling.

Men need to spread their seed

Differences in sexual politics are often explained away by the idea that guys “need” to experience sex with different partners as a means of “spreading their seed” before they can settle down with one woman. While women might snigger at this idea, there is some scientific research to back it up.

In August Dr Achim Schützwohl of Brunel University published research in Human Nature, claiming men are far more interested in casual sex than women. He asked 427 men and 433 women students from Germany, Italy and the US to record their responses to sexual advances from members of the opposite sex ranked as slightly unattractive, moderately attractive or exceptionally attractive.

He found men were far more likely to accept a sexual advance than women, and were less choosy about the attractiveness of their prospective bedfellow.

Casual sex is emotionally harmful

Conventional wisdom determines that sleeping with many different partners on a casual basis harms a person’s emotional well-being.

Not according to a study by the University of Minnesota, published in December. Researchers found the self-esteem and well-being of young adults who had last had a casual sexual encounter - a fifth of the 1 311 questioned - showed an emotional status no different from the others in committed relationships.

The researchers were surprised by the results and stressed that they in no way advocate casual sex which poses the physical risks of diseases and teen pregnancy.

Ejaculation shortens a man’s lifespan

Controversial book The Multi-Orgasmic Man: Sexual Secrets Every Man Should Know by Mantak Chia & Douglas Abrams claims that frequent ejaculation can drain a man’s energy and ultimately shorten his lifespan.

This is actually a widely held view in Chinese medicine. And a study published in August 2009 called Ejaculation Control and Mental, Spiritual, and Physical Health Part 9 found that there was a decrease in prostate cancer among the men with the lowest category of ejaculation frequency between 40 and 49 years old.

But other studies have proved frequent masturbation can cut the chances of contracting prostate cancer. – The Independent