Promiscuity is related to masculine and feminine body traits in both men and women: Evidence from Brazilian and Czech samples

• Either sex-typical or sex-atypical body traits relate to higher promiscuous tendencies in humans, particularly in women.
• We tested how individual variation in promiscuity relates to body dimorphism in men and women from two populations.
• Masculine and feminine body traits are independently related to promiscuity in both men and women, cross-culturally.
• Opposite lines of explanation can be intertwined and relationships between each body trait and promiscuity disentangled.

One of the possible explanations for human within-sex variation in promiscuity stems from conditional strategies dependent on the level of body sex-dimorphism. There is some evidence that masculine men and feminine women are more promiscuous than their sex-atypical counterparts, although mixed results persist. Moreover, another line of evidence shows that more promiscuous women are rather sex-atypical. We tested whether diverse sex-dimorphic body measures (2D:4D, WHR/WSR, handgrip strength, and height and weight) influence sociosexual desires, attitudes, promiscuous behavior, and age of first intercourse in a sex-typical or sex-atypical direction. Participants were 185 young adults, 51 men and 54 women from Brazil, and 40 men and 40 women from the Czech Republic. In men stronger handgrip and more feminine 2D:4D predicted higher sociosexual behaviors, desires, and lower age of the first sexual intercourse. While in women, sociosexual desires were predicted by lower handgrip strength and more feminine 2D:4D. It thus seems that it is rather a mixture of masculine and feminine traits in men, and feminine traits in women that increase their sociosexuality. Masculine traits (height) predicting female promiscuous behavior were specific for only one population. In conclusion, a mosaic combination of sex-typical but also sex-atypical independent body traits can lead to higher promiscuity, particularly in men. Limitations, implications, and future directions for research are considered.This article is part of a Special Issue entitled: Neotropical Behaviour.