Oral sex as infidelity-detection

An evolutionary history of human female infidelity and consequent sperm competition may have caused the evolution of male counter-adaptations. The infidelity-detection hypothesis for oral sex proposes that men perform oral sex to gather information about their partner’s recent sexual history. We tested this hypothesis with data secured from 231 men in committed, sexual, heterosexual relationships. We found support for two derivative predictions: men at a greater recurrent risk of sperm competition expressed greater interest in, and spent more time performing, oral sex on their partner, even after controlling statistically for relationship length, relationship satisfaction, and sexual intercourse duration. The discussion addresses limitations of this research and highlights directions for future research, including distinguishing empirically the infidelity-detection hypothesis from alternative hypotheses for oral sex.