A recent article in the Journal of Molecular Evolution shows that rates of evolution in primate reproductive genes are not higher than rates in nonreproductive genes. This is contrary to previous hypotheses, which have suggested that sperm competition in primates has led to accelerated evolution in reproductive genes. The authors looked at 653 seminal protein-coding genes in humans, chimpanzees, gorillas, orangutans, gibbons and macaques and found no elevated rates of nonsynonymous substitutions compared with a control dataset of nonreproductive genes. While the authors found seminal plasma genes as whole did not evolve more rapidly than the control set, certain categories of seminal genes show accelerated rates of evolution. Seminal plasma genes associated with certain broadly categorized functions such as “reproduction,” “immune response,” “response to stimulus,” and “metabolic processes” were shown to have elevated rates of protein changes.