To understand ways that Cascadia might reduce its rate of unplanned pregnancies, and slow the increase of its population, we’ve done a fair bit of research on, shall we say, reproductive behavior.

And in this field of learning, one puzzle keeps popping up.

Let’s set it up this way: William James’s doggerel captures an enduring truth, or is it myth?

Hogamous, higamous;
Men are polygamous.
Higamous, Hogamous;
Women monogamous.

Most survey research about sex supports this notion, that men are more promiscuous than women. But the notion is dubious-or, at least, overstated.

Consider, as a case in point, the grand kahuna of all sex surveys in the United States: the National Health and Social Life Survey. Supervised by Dr. Edward Laumann of the University of Chicago, this survey is the largest and most reliable of its kind in North America. Laumann and his team reveal in their tome on the study The Social Organization of Sexuality (University of Chicago Press, 1994) that straight women report having had five sex partners since they turned eighteen. Straight men report having had seventeen.

Got that? The average (the mean, not the median) woman has had sex with five men; the average man has had sex with seventeen women. Women take fewer than one third as many partners as men. Similar margins show up in other studies on both sides of the Atlantic.

  • Is this possible? No.

    As a matter of logic and mathematics, straight men and straight women must have (almost) exactly the same average number of sex partners. It takes two to tango.

    Why “almost exactly”? A few mathematical explanations from Laumann and others.

    1) The number of adult women exceeds the number of adult men in the United States by a few percentage points, because females survive through childhood and adulthood at higher rates than males. Statistically, this could only account for a tiny share of the discrepancy.

    2) Men have sex with teenage girls more often than women have sex with teenage boys, and the survey only asks respondents how many partners they have had since they were 18. The typical school-age mother, for example, conceives her child with an adult male, as discussed in Misplaced Blame. Still, the numbers of sexual relationships between adult males and minor females (as evidenced by surveys of teens, teen pregnancy rates, and the prevalence of sexually transmitted diseases among teens) are a tiny fraction of all sexual couplings. So this factor too could make only a small difference.

    3) Conceivably, men may have more sex partners in other countries than do women, though there’s no particular reason to believe they do. In fact, studies from other Western nations show the same pattern-men reporting more partners than women do-not the inverse and complementary pattern. And rates of international travel in America aren’t high enough to suggest that this explanation accounts for anything but a tiny share of the discrepancy.

    4) A share of straight men’s reported sex partners are undoubtedly women involved in prostitution. And women in prostitution may be dramatically underrepresented in the survey sample, because they are often hard to interview and reticent to give information. This explanation likely does account for a chunk of the discrepancy, but not a huge one. Prostitution would have to be far more ubiquitous than it actually is for it to more than triple men’s average number of sex partners.

    So what explains the wild disparity between men’s and women’s reports of how many people they have slept with? Lying. People lie on surveys, especially about sex.

    Men lie about their “conquests,” while women lie about their “virtue.” Throughout much of the world, promiscuous men are glamorized as “studs,” while promiscuous women are disparaged as “sluts.” Both men and women, therefore, have strong incentives to lean toward the social norm. And I suspect, though I can’t prove, that men inflate their count more than women deflate theirs. (Why? See page 46 in this feisty book by the ever-provocative Michael Males.) Guys seem more prone to wishful counting.

    William James amended: “Hogamous, higamous; Men say they’re polygamous.”