Sexual Partners – Who’s Exaggerating?
A piece by Gina Kolata in today’s New York Times caught my eye by posing a question I hadn’t considered – how is it logically possible for men to consistently report much higher numbers of heterosexual sex partners than women? As the reporter explains:
One survey, recently reported by the federal government, concluded that men had a median of seven female sex partners. Women had a median of four male sex partners. Another study, by British researchers, stated that men had 12.7 heterosexual partners in their lifetimes and women had 6.5.
But there is just one problem, mathematicians say. It is logically impossible for heterosexual men to have more partners on average than heterosexual women. Those survey results cannot be correct.
You might immediately think that a large number of men are having sex with the same few women, thus the number of actual women having multiple sex partners would remain low. In other words, some women would serve as hubs of sexual activity, and this indeed is suggested by one CDC employee, who provides a prostitute hypothesis for the discrepancy:
One is that men are going outside the population to find partners, to prostitutes, for example, who are not part of the survey, or are having sex when they travel to other countries.
Other researchers insist that the prostitute hypothesis could not possibly account for the size of the discrepancy in reported number of sexual partners. If women were serving as hubs of sexual activity, those women’s numbers of sexual partners would rise, affecting the average if they existed in great enough numbers, and there don’t seem to be enough “hubs” to make the difference.
As one interviewee explains,
By way of dramatization, we change the context slightly and will prove what will be called the High School Prom Theorem. We suppose that on the day after the prom, each girl is asked to give the number of boys she danced with. These numbers are then added up giving a number G. The same information is then obtained from the boys, giving a number B. Theorem: G=B Proof: Both G and B are equal to C, the number of couples who danced together at the prom. Q.E.D.”
Which model seems more realistic? Does the “proof” hold up under scrutiny? And are men exaggerating, women underestimating, or both?