Everything you always wanted to know about female ejaculation (but were afraid to ask)

by Sharon Moalem

Sharon Moalem is an evolutionary biologist and neurogeneticist at the Mount Sinai School of Medicine in New York City. His book, How Sex Works, was published this month in the US by HarperCollins

WHEN the British Board of Film Classification ordered 6 minutes and 12 seconds of material cut from British Cum Queens in 2002, they found themselves under attack from an unlikely quarter: a group of feminists.

The offending segment showed some of the female participants apparently ejaculating fluid from their genitals on orgasm. The film board stated that female ejaculation did not exist, so the actresses must have been urinating. And urinating on another actor on film is banned under the UK's Obscene Publications Act.

The group Feminists Against Censorship marshalled all the scientific evidence they could find to prove that some women do in fact ejaculate. The film board eventually backed down from its complete denial of the phenomenon, stating that female ejaculation was a "controversial and much debated area".

It was only a partial climbdown, however, as the film board insisted that the scenes in question were "nothing other than straightforward urination masquerading as ejaculation". In their defence, most pornography scenes that depict women ejaculating are indeed staged. Either the fluid is put into the vagina beforehand off-camera, or the actresses are simply urinating.

The dispute raises an intriguing question. In the 21st century, when human biology has been investigated right down to the genetic level, how can the existence of female ejaculation still be open to debate?

Medical textbooks are silent on this aspect of female physiology and most physicians never learn anything of it, unless of course they experience it themselves or witness it in their partners.

In the past few years, however, there has been an upsurge of research into the female sexual response. It seems that, even today, the human body may be harbouring a few surprises.

Although still controversial, many scientists now accept that some women can ejaculate some kind of fluid during sexual arousal or orgasm. Just how common it is, what the fluid is, and whether it serves any kind of function are some of the most hotly debated questions of sex research today, and I am playing a small part in helping to investigate them.

Many historical texts, such as the Kama Sutra, spoke about female "semen", as did writers, including the Greek physician Hippocrates. Sometimes the writers may have been referring to everyday vaginal secretions, which increase during sexual arousal. However, there are several references to something more akin to ejaculation. In the 17th century, the Dutch physician and anatomist Regnier De Graaf spoke of "liquid as usually comes from the pudenda in one gush".

In the last century, Ernst Gräfenberg, the German doctor who gave his name to the controversial G spot, drew attention to female ejaculation in a 1950 paper published in The International Journal of Sexology. "This convulsory expulsion of fluids occurs always at the acme of orgasm and simultaneously with it," he wrote. "Occasionally the production of fluids is so profuse that a large towel has to be spread under the woman to prevent the bed sheets getting soiled."

Most people did not take the paper seriously and thought Gräfenberg was probably describing a type of incontinence. It is certainly true that a few women experience loss of bladder control during sex, sometimes at the moment of penetration or at orgasm. But some who end up being investigated and even surgically treated for such "coital incontinence" may in fact be experiencing ejaculation. (And probably some who think they ejaculate may in fact be leaking urine.)

Ground-breaker

It is unknown how common genuine female ejaculation might be, or even whether it occurs solely on orgasm or merely during heightened sexual arousal. Just as with men's semen, women who believe that they are ejaculating report great variation in the nature and volume of the fluid produced. It can range from clear to milky-white in colour, and the amount of fluid can range from a few drops to more than a quarter of a cup.

The real ground-breaker came in 1981, when renowned US sexologists Beverly Whipple and John Perry published a case report of a woman apparently happy to ejaculate under laboratory conditions. Watched by a team of researchers, the woman was vaginally stimulated by her husband until she reached orgasm, climaxed, and then ejaculated, releasing noticeable amounts of fluid.

According to Whipple, when Philadelphia gynaecologist Martin Weisberg saw their report he said: "Bull... I spend half my waking hours examining, cutting apart, putting together, removing or rearranging female reproductive organs... Women don't ejaculate."

In response, Whipple offered to set Weisberg up with a personal demonstration. The following is Weisberg's description of what he witnessed, which was later included in Whipple and her co-author's bestselling book, The G Spot and Other Recent Discoveries About Human Sexuality: "The subject seemed to perform a Valsalva manoeuvre [bearing down as if starting to defecate] and seconds later several cc's of milky fluid shot out of the urethra."

Impressive as that demonstration sounds, it is interesting to note that the fluid appeared to emerge from the urethra, the tube that drains urine from the bladder to an exit near the entrance of the vagina (see diagram). Could it have been urine after all?

Not according to chemical analysis of the fluid, carried out by Whipple and a few others since then. They found the ejaculate contained very low levels of urea and creatinine, the two main chemical hallmarks of urine.

One marker it did contain, however, was prostate-specific antigen, or PSA. That's the same chemical produced by the prostate gland in men.

The male prostate is usually around the size of a walnut, weighing about 23 grams. It surrounds the urethra like a doughnut and is encased by a fibromuscular sheet, which contracts during ejaculation to help expel prostatic fluid into the urethra, where it mixes with the other components of semen.

Less widely known is that women have prostate tissue too. And this, it seems, is the best candidate for the source of female ejaculate. Also known as the Skene's glands or the paraurethral glands, in 2001 the Federative Committee on Anatomical Terminology officially renamed these structures the "female prostate".

The female prostate seems to vary in size and shape much more than the male version, with some women lacking any appreciable amount of prostate tissue, according to autopsy studies by Slovakian pathologist Milan Zaviacic. This may explain women's differing experiences.

G spot

If the tissue is there at all it lies next to, or sometimes surrounds, the urethra, which is adjacent to the vagina's anterior wall. In other words, if the woman is lying on her back, the prostate is directly above the uppermost wall of her vagina.

This is roughly the same area as the G spot, the part of the vagina that is particularly sensitive to stimulation, although even the G spot's existence is controversial. Assuming there is such a thing, however, it is beginning to look to many sexologists as if the G spot is just the name for the best place to stimulate a woman's prostate. Variation in the amount of prostate tissue could explain why not all women find stimulation of this area arousing - in other words, whether or not they have a G spot

When anatomy textbooks show the female prostate - and not all do - the gland tissue is sometimes shown with ducts draining fluid to two pinhole-sized openings next to the urethra, just above the vagina. Others, however, suggest there may be as many as 20 ducts, and that they drain into the urethra, near its external opening (as shown above).

One of the more interesting reports on female ejaculation was published in 2007 by a team led by Florian Wimpissinger, an Austrian urologist at Rudolfstiftung Hospital in Vienna (The Journal of Sexual Medicine, vol 4, p 1388).

Two women in their 40s came to the attention of the researchers after they attended a sexual medicine clinic because of "significant fluid expulsion during orgasm". The women agreed to produce samples of the fluid by masturbation in the lab. When analysed, this fluid was found to be chemically distinct from urine, with high PSA and other features more akin to male ejaculate.

Ultrasound scans showed that both women had large prostate glands. One woman's scan showed "a hyperintense structure surrounding the entire length of the urethra", which "closely resembles that of the male prostate", according to the authors. By inserting a fine flexible tube with a camera on the end into the urethra, the researchers could see a duct exiting just inside the entrance to the urethra.

The team has another paper due to be published in The Journal of Sexual Medicine next month, describing how they used MRI scans to investigate the prostate of seven women who attended a urology clinic. In this study, however, the team did not find a correlation between prostate size and the ability to ejaculate. Larger studies of this kind are obviously needed.

Partly thanks to the growing body of research in this area, there seems to be increasing awareness of female ejaculation among the general public. Some sex educators provide workshops claiming to teach women how to ejaculate (as well as how to discover their G spots and have more orgasms).

One question that is rarely addressed, however, is whether female ejaculation has a biological function. Not every aspect of our physiology has to have such a role. For example, men are thought to have nipples only because women need them, and male and female embryos develop from the same body plan. Some have even cited this as the reason why women orgasm. Perhaps female ejaculation has a similar explanation.

On the other hand, it is tempting to speculate about what purpose female ejaculation could fulfil. Whipple and Perry have suggested that female ejaculation evolved to combat infections of the urethra and bladder. Many secretions and fluids produced by the human body, such as saliva, tears, and indeed male ejaculate, are awash with compounds that inhibit the growth of bacteria.

Urinary tract infections are relatively common in women, and sometimes arise from bacteria spread to the urethra during sex. A gush of antimicrobial fluid at the entrance to the urethra around the time of sex might help fight off such bacteria.

Along with my colleagues I am investigating whether female ejaculate contains some of the antimicrobial chemicals present in semen, such as zinc. If so, then this fascinating and long-neglected phenomenon might turn out to be more than just a sexual curiosity.