The testosterone regulations in women's athletics are a series of policies first published in 2011 by the IAAF (now World Athletics) and last updated following a court victory against Caster Semenya in May 2019. The first version of the rules applied to all women with high testosterone, but the current version of the rules only apply to athletes with certain XY disorders of sexual development, and set a 5 nmol/L testosterone limit, which applies only to distances between 400 m and 1 mile (inclusive), other events being unrestricted.
Athletes are allowed to compete in the restricted events with medical suppression of testosterone (by contraceptive injections or pills, or physical castration), although in practice many have chosen to switch to unaffected events, most notably the 200m.[1]