Caster Semenya, the world and Olympic 800m champion, will go to the Court of Arbitration for Sport to fight "unfair" regulations that hinder certain female athletes.
The IAAF brought in controversial new rules in April that mean some women with high natural testosterone levels could be excluded from middle-distance races.
Semenya, a two-time Olympic and three-time world champion, is the highest-profile athlete expected to be impacted by the rules that divide medical opinion.
The South African's lawyers, Norton Rose Fulbright, which has offices in London, issued a statement yesterday saying the athlete would "file the legal challenge to ensure, safeguard and protect the rights of all women on the basis the regulations are irrational, unjustifiable, and in violation of the IAAF Constitution (based in Monaco), the Olympic Charter, the laws of Monaco, the laws of jurisdiction in which international competitions are held, and of universally recognised human rights.
"Caster Semenya contends the regulations are objectionable on numerous grounds, including that they compel women with no prior health complaints to undergo medical interventions to lower their testosterone levels," the statement added.