When two researchers at Chapman University in California began to study whether tall heterosexual men have had more sex partners than other heterosexual men, they assumed the answer would be “yes.” There was already extensive academic literature showing that height signals dominance, physical (and hence heritable) fitness, and social status to women who are seeking sex partners.
To their surprise, that’s not what they found. Tall men don’t have a history of more sex partners than men of average height or most short men, according to their study in the latest online issue of Evolutionary Psychology. After dividing respondents into different height groups, the researchers found that every group of men taller than 5 feet 4 inches had the same median number of sex partners: seven. Only men classified as “very short,” or between 5 feet 2 inches and 5 feet 4 inches, had a significantly different sexual history. They reported a median of five sex partners.
The research drew on the experiences of 60,058 heterosexual U.S. men and women ages 18 to 65 who completed an anonymous online survey in 2006.1
According to the authors, David Frederick and Brooke Jenkins, the explanation for their findings might be that women have a “minimal threshold” for male height — anyone taller is pretty much an acceptable potential mate and anyone shorter, not so much.
Women who were “very short” (4 feet 11 inches or shorter) also reported having a median of five sexual partners, the lowest of all female height groups. However, since the researchers held no theories about a female’s height and her number of sex partners before conducting their research, they didn’t further explore those findings.
The authors also calculated the average number of sex partners for the different groups. The averages were much higher than the medians, but they (and I) am keen to focus on the medians here. Just as it only takes a couple of billionaires to skew the numbers on average income, a handful of very prolific sexual players in this data set could be driving up those averages.
The authors weren’t only interested in whether there is a connection between male height and number of sex partners; they also looked at body mass. And in that area, their findings were pretty consistent with their initial theory: Men in the “obese,” “overweight” and “normal weight” categories had a higher median number of sex partners than those who were underweight or severely obese.2
For women too, those who were underweight reported a lower median number of sex partners than those with a higher body mass index. Speaking on the phone, Frederick said there were two possible explanations. The first, he said, is that “underweight women are choosier because they’re in a position to be choosier.” In other words, if society deems underweight women more attractive than heavier women, those women can be more selective on the mating market. His alternative theory is that underweight women might have a negative body image or even eating disorders — both of which might affect their desire to physically reveal themselves and have sex.
That second theory touches on a bigger issue here: Libido might vary with height and weight. If so, an individual’s desires could be just as important as how desirable they are to others in affecting the median number of sex partners. When I suggested this to Frederick, he said that it was possible that hormones affecting an individual’s sex drive might vary with height and weight but that he didn’t want to speculate.
There’s another important thing to keep in mind when interpreting this data: The number of sex partners people have had might not be the best indicator of how desirable they are. It’s possible that someone might be highly sexually desirable but choose a monogamous or celibate lifestyle for an extended period of time. Also, “sex” was not defined in the survey, so participants might have differed in their interpretation of “sex partner” when providing their responses.
Other caveats are more typical of this type of research. The survey offers a snapshot, while sex partners accrue over a lifetime. It’s possible that some individuals who were of normal weight gained most of their reported sex partners at a previous time when they were overweight or vice versa. The online survey also doesn’t offer a nationally representative sample of the U.S. population. And, of course, it’s possible that respondents failed to accurately remember their height, weight or number of sex partners — or that they flat-out lied about some or all of those variables. Despite that, the study offers a fascinating insight into the sexual histories of a large number of heterosexual people. And lays the groundwork for yet more research into “short man syndrome.”