Perhaps the most common evidence offered in support of males and females having evolved different sexual psychologies is from numerous surveys that show, across cultures, that men report having many more sexual partners than women. This is argued to reflect a basic underlying genetic fact: the best investment for a male to generate the maximum number of offspring with his genes is to impregnate as many females as possible. A woman has to invest much more in her offspring and is better served by selected fewer male partners who are more likely to provide support for her and her children.
Gina Kolata, in the Aug. 12 N.Y. Times, reports an interesting slant on this story. Simple math shows that the numbers don't add up... she quotes David Gale of U.C. Berkeley:
Surveys and studies to the contrary notwithstanding, the conclusion that men have substantially more sex partners than women is not and cannot be true for purely logical reasons...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.Sex researchers know that this is correct. Men and women in a population must have roughly equal number of partners. So why do men report many more than women? They exaggerate? They go to prostitutes who don't appear in the survey? (The latter would not explain the huge difference in reporting.) The most likely explanation:
...the survey data themselves may be part of the problem. If asked, a man, believing that he should have a lot of partners, may feel compelled to exaggerate, and a woman, believing that she should have few partners, may minimize her past...In this way the false conclusions people draw from these surveys may have a sort of self-fulfilling prophecy.