The process of testing to determine gender in putatively female athletes was developed in order to prevent cheating, but has devolved instead into a clumsy mechanism for detecting disorders of sexual development (DSD's). In over thirty years of compulsory testing, individuals with DSD's have been stigmatized and some have been denied the right to compete, although frequently their condition provided no competitive advantage. More recent guidelines require testing only on a case-by-case basis; the South African runner Caster Semenya was the first major test of this policy, and her experience points to the need for a more sensitive and confidential process. In addition, her case dramatizes the inadequacy of the term "gender verification." Gender identity is a complex entity and resists simple classification. Sports authorities may set guidelines for who can compete, but they should refrain from taking on themselves the authority to decide who is and who is not a female.