http://www.sciencemag.org/news/2018/07/top-stories-transgender-athletes-water-mars-and-climate-cooling-arachnid > This scientist is racing to discover how gender transitions alter athletic performance—including her own > In 2015, Joanna Harper, a medical physicist and runner, published the first study of transgender athletes’ race times, finding no advantage for transgender women who had been receiving hormone therapy, thanks to their previous exposure to male levels of testosterone. The groundbreaking study launched Harper into an advisory role for organizations such as the International Olympic Committee that are revising rules for transgender competitors. Harper—who herself transitioned more than a decade ago—is in the middle of the biggest study to date to examine athletic performance during gender transitions.