Mapping the way to G-spot utopia

What's more, these glands and erectile tissue were awash in the same active enzymes in the penis that respond to drugs such as Viagra. The structures were likely candidates for the mechanism of the G spot, and the evidence, published in the journal Urology, hinted that only some women had them. (How many women, however, is still unclear; the study was too small to make estimates.)

But there was a big problem, says Emmanuele Jannini, professor of experimental medicine at University of L'Aquila in Italy, who led the investigation. The study had to rely on autopsy results from women whose bodies had been donated to science. There was no way to know whether the special tissue and glands made any difference sexually.

So Jannini decided to examine the pelvises of living women using ultrasound imaging. His study, published in March in the Journal of Sexual Medicine, looked at 20 women, about half of whom said they experienced "vaginal orgasms" through the stimulation of the front wall of the vagina alone.

This vaginal-orgasm group tended to have slightly thicker tissue than did the clitoral-orgasm group, the team found -- about a 2-millimeter difference along the upper wall between the vagina and the urethra. Although ultrasound images can't show exactly what's in there, it's the same place that Skene glands and erectile tissue from the inner bulb of the clitoris are likely to be.

Plenty of nerves suffuse this area, says Barry Komisaruk, psychology professor at Rutgers University, who was not involved in the study. The vagina and clitoris each have different kinds of nerves, and because the male prostate is richly innervated, it's possible that the Skene glands have their own kind as well.

But without further study, it's impossible to understand how the nerve networks in women with thicker tissues might be different, Komisaruk says. Nor does science know whether stimulating this spot leads to the bigger, deeper orgasms of G-spot legend. But, he says, the area's different nerves lead to different parts of the brain, each producing their own sensations. "So stimulating a combination of nerves might be synergistic, leading to a unique sensation and to more complex orgasms." His preliminary work shows that different regions of the brain perk up when women stimulate their front vaginal wall, say, as opposed to their clitoris or cervix.