"As an erectile body, this structure is causing elevation of the [front of the] vaginal wall at the beginning of the sexual excitement," Ostrzenski tells WebMD.

The alleged G-spot is a tiny bunch-of-grapes-like structure within a bluish sac buried deep within the front wall of the vagina , says Adam Ostrzenski, MD, PhD, of St. Petersburg, Fla.

April 25, 2012 -- The elusive G-spot has been called the UFO of gynecology -- but now a retired surgeon says he has photographic proof it exists.

G-Spot? Maybe Not

But Ostrzenski's finding is based on a single dissection, performed on a recently deceased 83-year-old woman.

"The feeling in my limited field is that this is not real," Elena Ratner, MD, assistant professor of obstetrics, gynecology, and reproductive medicine at Yale University, tells WebMD via email.

Ratner notes that findings from a single dissection, performed on an elderly woman, are not proof that the structure is common to all women -- or that it is a source of sexual sensation.

"Who is to say that this thing they found on her dissection was the center of pelvic pleasure?" Ratner asks.

Even more dismissive of Ostrzenski's claim is sex therapist Leonore Tiefer, PhD, clinical associate professor of psychiatry at New York University Medical Center.

"We can conclude absolutely nothing from this paper since we know nothing about the sexual life of the dead woman," Tiefer tells WebMD via email.

While warning that nothing is proven by a single case, Christopher Estes, MD, assistant professor of obstetrics and gynecology at the University of Miami, does not dismiss Ostrzenski's report.

"This certainly is suggestive of an anatomical structure that would correlate with a G-spot," Estes tells WebMD. "Women who experience orgasms from a G-spot will describe a hardening on the inside of the vagina, a little almond- or peanut-shaped protuberance. This is consistent with that."

The G-spot, in 1981 named the Grafenberg zone after Ernst Grafenberg, was christened the "G-spot" in media reports. The area, variously described as somewhere in the front of the vagina, is a source of sexual stimulation to about 50% of women.