Caster Semenya will appeal against World Athletics' rule restricting testosterone levels in female runners to the European Court of Human Rights.
The double Olympic 800m champion, 29, lost two previous appeals to the Court of Arbitration for Sport (Cas) and Switzerland's Federal Supreme Court.
The South African's lawyers confirmed her further appeal on Tuesday.
https://twitter.com/Muftawu_Nabila/status/1328755394630594561"Public support goes a long way to help show how the rules from World Athletics are against public interest," said Greg Nott, a member of Semenya's legal team.
"As such, we encourage everyone to help create a more equal world by showing their support on social media and by putting pressure on their sporting bodies to embrace and apply internationally accepted human rights values in their activities and rules."
Athletics' governing body brought in a rule in 2019 that athletes with differences of sexual development (DSD) must either take medication in order to compete in track events from 400m to the mile, or change to another distance.
Athletes with DSD have higher levels of natural testosterone, which World Athletics believes gives them a competitive advantage.
Cas rejected Semenya's challenge against the rule last year before the Swiss Federal Supreme Court also denied her appeal in September.
Following the second ruling, World Athletics said: "We welcome the decision by the Swiss Federal Tribunal to uphold our DSD regulations as a legitimate and proportionate means of protecting the right of all female athletes to participate in our sport on fair and meaningful terms."
The ruling means Semenya, who won Olympic gold in 2012 and 2016, will not be able to defend her 800m title at the rearranged Tokyo Games next summer.
In March, she said she wants to compete in the 200m, a distance for which she would not need to take medication, in Japan.
