Two-time Olympic champion Caster Semenya won't be defending her title in the 800-meter event of September's world track championships. 

On Tuesday, Semenya was declared ineligible to run the 800-meter event after the Swiss Supreme Court ruled that testosterone levels and restrictions were going to be placed on athletes.

Caster Semenya of South Africa, a two-time Olympic champion at 800 meters, will not be eligible to run her signature event at this year's world track and field championships after the latest legal ruling in an ongoing, highly-charged case about testosterone levels and restrictions placed on intersex athletes to compete in certain women's events.

Semenya sustained a setback on Tuesday, when the Swiss Supreme Court reversed a decision it made in June and, temporarily at least, reimposed the hormone restrictions set forth by track and field's world governing body in women's events from 400 meters to the mile.

In addition, Semenya's attorney, Dorothee Schramm, stated that she plans to appeal the decision on behalf of Semenya. She wants to overturn eligibility rulings on athletes "who have disorders of sexual development and possess X and Y chromosomes, the normal male pattern."

"I am very disappointed to be kept from defending my hard-earned title," Semenya said in a statement following the ruling. "His will not deter me from continuing my fight for the human rights of all of the female athletes concerned."

Semenya is hyperandrogenous, which means that her body produces large amounts of testosterone. Testosterone helps athletes build muscle while their body grows. According to USA Today, experts believe that intersex athletes such as Semenya develop internal testes during puberty and, while it keeps their gender that same, grants them "an unfair advantage."

The International Association of Athletics Federations is holding on making any decisions until the Swiss Supreme Court releases a more detailed report of their findings. That information is scheduled to be released on Wednesday.

It was originally expected that Semenya would be able to participate in the 800-meter event at the world track championships, which are scheduled to take place from Sept. 28-Oct. 6 in Doha, Qatar. In June, the Swiss Supreme Court "temporarily suspended" rules that oversaw testosterone levels and that would've allowed Semenya to compete.

Semenya has won gold medals in the 2012 and 2016 Olympic games and would likely be a favorite in Toyko as long as she's cleared to compete. However, it's worth noting that the International Olympic Committee uses the IAAF's rules to determine eligibility.