The debate is as old as physical competition. Are stars like Usain Bolt, Michael Phelps, and Serena Williams genetic freaks put on Earth to dominate their respective sports? Or are they simply normal people who overcame their biological limits through sheer force of will and obsessive training? Researchers have slowly begun to uncover how the relationship between biological endowments and a competitor’s training environment affects athleticism. Sports scientists have gradually entered the era of modern genetic research.