Adaptation to Sperm Competition in Humans

Abstract

With the recognition, afforded by recent evolutionary science, that female infidelity was a recurrent feature of modern humans' evolutionary history has come the development of a unique area in the study of human mating: sperm competition. A form of male–male postcopulatory competition, sperm competition occurs when the sperm of two or more males concurrently occupy the reproductive tract of a female and compete to fertilize her ova. Males must compete for mates, but if two or more males have copulated with a female within a sufficiently short period of time, sperm will compete for fertilizations. Psychological, behavioral, physiological, and anatomical evidence indicates that men have evolved solutions to combat the adaptive problem of sperm competition, but research has only just begun to uncover these adaptations.