Math, Men, Women.
It is widely held that men are more promiscuous than women and no doubt there is some truth to it. The problem comes when one tries to quantify it. Several studies claim to have concluded that, on average, men have more sexual partners than women. The thing is, assuming an almost equal number of males and females in a population, that conclusion is impossible. This amusing article in NYT provides a proof.
“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.
Proof: Both G and B are equal to C, the number of couples who danced together at the prom. Q.E.D.”
Now assume that number of men is equal to the number of women. It follows that the average number of partners for men and women is also the same. Even if we take into account the slightly smaller number of men, the averages should not be as different as some studies suggest (4 for women and 7 for men).
The article provides some possible explanations for the conclusions of these studies. But the fact remains that one can't trust any study which claims the unprovable.