Caster Semenya, the two-time Olympic champion from South Africa in the 800 meters, said Monday that she would legally challenge track and field’s world governing body, attempting to block a much-debated rule that seeks to limit the permitted testosterone levels in female athletes in races over certain distances.

Semenya, 27, called the rule, which is scheduled to go into effect in November for races from 400 meters to one mile, medically unnecessary, “discriminatory, irrational, unjustifiable” and a violation of the rules of sport and universally-recognized human rights.

Semenya said the rule stigmatized women who do not conform to perceived notions of femininity and permitted discrimination against them. She argued that she should be able to compete the way she was born without “being obliged to alter her body by any medical means,” according to a statement released by her lawyers.

Her legal challenge is being made to the Swiss-based Court of Arbitration for Sport, a kind of Supreme Court for international sports.