Human Sperm Competition: A Comparative Evolutionary Analysis

Sperm competition occurs when a female copulates with two or more males within a sufficiently brief time period, resulting in sperm of the different males competing to fertilize ova. Sperm competition has been documented or inferred to occur across several species. We address the evidence for sperm competition in humans by reviewing literature indicating apparently convergent adaptations to sperm competition in humans and non-humans. We discuss future research directions, and conclude that the evidence for anatomical, biological, physiological, and behavioral adaptations to human sperm competition provides compelling evidence that sperm competition has been a recurrent feature of human evolutionary history.