Size, not foreplay, is what fulfils women's sexual fantasies

Lead researcher Stuart Brody, from the University of the West of Scotland, focused on the number of factors that contributed to the regularity of vaginal orgasms.

The researchers described a vaginal orgasm as an "orgasm produced simply from movements of the penis in [the] vagina without any additional stimulation."

Boffins found that factors like the length of the penis, the duration of intercourse, and the ability to mentally focus on vaginal sensations, minus the duration of foreplay, increased the likelihood of orgasm.

"Given that the vagina [has a high nerve density] throughout… more thorough stimulation of the full length of the vagina… might result in a more fulfilling experience," ABC Science quoted the paper''s authors as saying.

But some Australian researchers and practitioners have cast a shadow of doubt over the methodology and the political motivations behind the study.

Dr. Gemma O''Brien, a reproductive physiologist from the University of New England in Armidale, said: "Self reporting needs to be done very carefully. These things come down to perceptions and that introduces a weakness in the study."

Dr. Vivienne Cass, an adjunct professor at Curtin University of Technology in Perth and author of The Elusive Orgasm, also questioned the motivations of research that accorded vaginal orgasms greater significance over clitoral ones.

Associate Professor Rosemary Coates, also of Curtin University of Technology and president of the World Association for Sexual Health, also said "some form of clitoral stimulation is almost always required to trigger orgasm."

The results appear in an upcoming issue of The Journal of Sexual Medicine.