The International Association of Athletics Federations (IAAF) requires the blood testosterone level of female athletes with differences of sex development to be reduced to below 5 nmol/L for a continuous period of at least 6 months, and thereafter to be maintained to below 5 nmol/L continuously for as long as the athlete wishes to remain eligible. Its ruling is based on questionable research findings. Medical decisions and interventions should be based on evidencefrom well-designed and well-conductedresearch and confirmatory studies. Caster Semenya, the reigning 800-meter Olympic champion since 2015, has challenged this ruling. Gender verification was instituted with women's participation in the Olympics in 1900, and female athletes were subjected to invasive, embarrassing and humiliating procedures. In its many decades of harsh scrutiny of successful female athletes, especially those from backgrounds similar to Semenya's, the IAAF has disrespected human rights and medical ethics and allowed prejudice, discrimination and injustice to infringe on their dignity and relentlessly obstruct their international sporting careers.