Transgender Swimmer in College Athletics

There is current scientific and legal controversy about sports competition eligibility regulations for transgender athletes. To better understand and contextualize the effect of androgen-suppression treatment on swimming performance, we compared the gender-related differences in performance of a transgender swimmer who competed in both the male and female NCAA (collegiate) categories to the sex-related differences in performance of world and national class swimmers. These data demonstrate that the gender-related differences in middle distance freestyle performances of a transgender woman are smaller than the observed sex-related differences in performance of top athletes. Our analysis may be useful as a framework for regulators considering participation guidelines which promote fair competition for all athletes, whether cisgender or transgender. One-Sentence Summary Recent outstanding performances by a transgender woman swimmer are faster than predictions based on historic sex-related differences in swimming performance.