Elite athletic competitions have separate male and female events due to men's physical advantages in strength, speed, and endurance so that a protected female category with objective entry criteria is required. Prior to puberty, there is no sex difference in circulating
testosterone concentrations or athletic performance, but from puberty onward a clear sex difference in athletic performance emerges as circulating
testosterone concentrations rise in men because testes produce 30 times more
testosterone than before puberty with circulating
testosterone exceeding 15-fold that of women at any age. There is a wide sex difference in circulating
testosterone concentrations and a reproducible dose-response relationship between circulating
testosterone and muscle mass and strength as well as circulating
hemoglobin in both men and women. These dichotomies largely account for the sex differences in muscle mass and strength and circulating
hemoglobin levels that result in at least an 8% to 12% ergogenic advantage in men. Suppression of elevated circulating
testosterone of hyperandrogenic athletes results in negative effects on performance, which are reversed when suppression ceases. Based on the nonoverlapping, bimodal distribution of circulating
testosterone concentration (measured by liquid chromatography-mass spectrometry)-and making an allowance for women with mild
hyperandrogenism, notably women with
polycystic ovary syndrome (who are overrepresented in elite athletics)-the appropriate eligibility criterion for female athletic events should be a circulating
testosterone of <5.0 nmol/L. This would include all women other than those with untreated hyperandrogenic
disorders of sexual development and noncompliant male-to-female transgender as well as
testosterone-treated female-to-male transgender or
androgen dopers.