Ok, I know that the alternative would perhaps be even sillier and that this is not relevant to the validity of such studies but juvenile that I am, I couldn't help mentioning it.
So anyway, here are a couple of nice...tit bits...from recent research, presented at the International Society for Human Ethology Conference, Maine in July 2009:
The ease of orgasm from heterosexual penetrative sex in women is positively correlated with the ratio of first finger to third finger length - that is, the more that your third finger is longer than your first, the greater your 'coital orgasmic ability' (Lara Eschler, Cambridge University. I can't seem to find this as a published study, but she's a PhD student so I assume the data comes from her ongoing work).
Female orgasm during heterosexual vaginal intercourse is not correlated with the intensity of orgasmic vocalisation. Though greatest reported frequency of orgasm occurred during non-intercourse sexual activity, the greatest intensity of vocalisation occurred immediately prior to or during male orgasm (Brewer, Morgan and Hendrie - 'On the adaptive significance of female copulatory vocalisations', from the University of Central Lancashire and the University of Leeds - again as yet unpublished as far as I can tell).
