From The New York Times:
Take the question of promiscuity. Everyone has always assumed — and early research had shown — that women desired fewer sexual partners over a lifetime than men. But in 2003, two behavioral psychologists, Michele G. Alexander and Terri D. Fisher, published the results of a study that used a “bogus pipeline” — a fake lie detector. When asked about actual sexual partners, rather than just theoretical desires, the participants who were not attached to the fake lie detector displayed typical gender differences. Men reported having had more sexual partners than women. But when participants believed that lies about their sexual history would be revealed by the fake lie detector, gender differences in reported sexual partners vanished. In fact, women reported slightly more sexual partners (a mean of 4.4) than did men (a mean of 4.0).
So how sketchy is the research on human sexual behavior, anyway?
The numbers don't need to match, even if everyone was counted and reported accurately.
To take some extreme examples:
The population is Alex, Betty, Carrie, Daphne. Alex hooks up with each of the others. Mens' average: 3. Womens' average: 1.
Now take Alice, Bob, and Cindy. Alice hooks up with Bob and then leaves the population (emigrates or dies) Womens' average: 0. Mens' average: 1
In the Cracked article I first saw this in (can't say if OrphanWilde got it from elsewhere) they admitted that there could be a gender ratio imbalance (they also pointed out that homosexuals exist) but noted that the evidence was being interpreted strictly as evidence for promiscuous males. (And ... whatever the opposite of promiscuous is ... females.)