Gender verification of female athletes has long been criticized by geneticists, endocrinologists, and others in the medical community. Problems include invalid screening tests, failure to understand the problems of intersex, the discriminatory singling out of women based only on laboratory results, and the stigmatization and emotional trauma experienced by individuals screened positive. Genuine sex-impostors have not been uncovered by laboratory-based genetic testing; however, gender verification procedures have resulted in substantial harm to a number of women athletes born with relatively rare genetic abnormalities. Individuals with sex-related genetic abnormalities raised as females have no unfair physical advantage and should not be excluded or stigmatized, including those with 5-alpha-steroid-reductase deficiency, partial or complete androgen insensitivity, and chromosomal mosaicism. In 1990, the International Amateur Athletics Federation (IAAF) called for ending genetic screening of female athletes and in 1992 adopted an approach designed to prevent only male impostors from competing. The IAAF recommended that the "medical delegate" have the ultimate authority in all medical matters, including the authority to arrange for the determination of the gender of the competitor if that approach is judged necessary. The new policy advocated by the IAAF, and conditionally adopted by the International Olympic Committee, protects the rights and privacy of athletes while safeguarding fairness of competition, and the American Medical Association recommends that it become the permanent approach.