Noted NY Times science reporter
Gina Kolata writes:
Everyone knows men are promiscuous by nature. ...
Surveys bear this out. In study after study and in country after country, men report more, often many more, sexual partners than women.
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. ...
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.
It is about time for mathematicians to set the record straight, said David Gale, an emeritus professor of mathematics at the University of California, Berkeley.
No, there is no logical contradiction. It is quite plausible that men have a higher median number of sex partners, as I've discussed
here. It can be explained by a small number of women having a lot of sex partner. That is, most men have more sex partners than most women, but a few slut outdo everyone by a wide margin. That's the way it is with the people I know, anyway.
Kolata gives the explanation that men exaggerate while women minimize their misbehavior. But she ignores other possible explanations, such as men having a different definition from women. These surveys don't usually define a sex act or sex partner, and people really do have different definitions.
Update: A reader cites
this:
Women are more likely than men to lie about their sex lives, reveals a new study. ...
Women change their answers depending on whether or not they believe they will be caught out not telling the truth, the researchers found. The number of sexual partners a woman reported nearly doubled when women thought they were hooked up to a lie detector machine.
The reader also gives an example where the median can be different from the mean. A small number of sluts can increase the averages, and increase the median for men, but not affect the measured median for women. But Kolata says:
Dr. Gale added that he is not just being querulous when he raises the question of logical impossibility. The problem, he said, is that when such data are published, with no asterisk next to them saying they can’t be true, they just "reinforce the stereotypes of promiscuous males and chaste females."
The suggestion here is that the study authors are publishing inconsistent data, and failing to even notice that the problem. But that is just not true about the govt study cited above. Here is the
USA CDC study. This
AP story on it even has a correction:
(This version CORRECTS that figures for lifetime sexual partners were median figures, not averages.)
Now Kolata and Gale should issue a correction because the CDC study measured the median, and it probably is true that men have a higher median number of sex partners than women.
I mentioned this CDC study before
here.
Justoneminute makes a similar point, and gives a nice explanation as why median and mean are different in this case.