In this rather odd NYTimes article, it says that men have, in median numbers, more heterosexual partners than women do. Gina Kolata, upon consulting some mathematicians, says this is impossible. The economists over at Crooked Timber, think differently. Meanwhile, the larger question is, why are these numbers unequal? Regardless if the numbers are right, women either say they have fewer partners or they actually do. I would say it largely has to do with a social standard. Men are expected to have more partners. A man with a lot of sexual partners is a "player" whereas a woman with a lot of sexual partners is a "slut." Now, economists, you tell me who has more incentive to rack up the numbers.
Cross-posted at Campus Progress.