To explain the apparent incongruity, Eleftheriou’s co-author Roger Ingham, a sexual health expert at the University of Southampton, offered two possible reasons. First, it is lack of contraception as an evolutionary holdover, he wrote to The Washington Post in an email. That is, “men want to reproduce with women they find to be more attractive,” he said. Or it could be that young men attach high status to having sex with attractive women, “and so are willing to take more risk to acquire this status.” Or, perhaps, it is a mixture of both motivations.

When asked if the reverse would seem to hold true — are men more likely to use condoms with women whom they find less desirable? — Eleftheriou replied, “Yes. We found a strong correlation between the two variables that works both ways.”