Why Do Men Report More Opposite-Sex Sexual Partners Than Women?

Perhaps male bragging and female avoidance of being considered slutty?

Some excerpts:

In a closed population and defined time period, the mean number of opposite-sex partners reported by men and women should be equal. However, in all surveys, men report more partners. This inconsistency is pivotal to debate about the reliability ofself-reported sexual behavior.We used data from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), a probability sample survey ofthe British population, to investigate the extent to which survey sampling, accounting strategies (e.g., estimating versus counting), and (mis)reporting due to social norms might explain the inconsistency. Men reported a mean of 14.14 lifetime partners; women reported 7.12. The gender gap of 7.02 reduced to 5.47 after capping the lifetime partner number at the 99th percentile. In addition, adjusting for counting versus estimation reduced the gender gap to 3.24, and further adjusting for sexual attitudes narrowed it to 2.63.


"Our analysis of nationally representative data suggests that
almost two-thirds of the gender gap in number of lifetime partners reported by men and women in Britain may be explained by three factors: a greater propensity among men to report extreme values; a greater propensity among women to count rather than estimate their lifetime partners; and gendered differences in attitudes toward casual and nonexclusive sex. The disparity seems barely affected by gender differences in the reported number of lifetime paid-for partners, but gender differences in reported non-U.K.-resident sexual partners have a modest (nonsignificant) impact in a five-year period and cannot be discounted as a potential explanation over the lifetime. Men were more likely than women to exclude oral-sex-only partners from their total count, and so adding them back in led to a slight (nonsignificant) widening of the gap."

"Changes over time (period effects) may also provide an explanation, if over time it has become less “socially undesirable” for men to report few partners and for women to report many partners."

"Previous studies suggest that women increase their reported number of partners more than men when they think they are attached to a lie detector (Fisher, 2013), and studies of survey mode show that women increase their estimates of lifetime partners with Web versus telephone surveys, whereas men’s estimates stay constant (Brown et al., 2017)."