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DSD Athletes: What Does it Mean And What Are the World Athletics Rules?

What is “differences of sexual development,” and how do the rules affect women’s track and field? An explainer.

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The term “DSD” has been referenced a lot during the Tokyo Olympics, but the complex health condition is never fully explained on television broadcasts as the athletes who have differences of sexual development compete, and the meaning of DSD athletes hasn’t been made clear.

At the Tokyo Olympics, for example, Christine Mboma, 18, of Namibia won the silver medal in the 200 meters. It’s an event that she decided to compete in, along with her countrywoman Beatrice Masilingi (sixth place), because they were banned from racing the 400 meters due to their DSD conditions. Similarly, the 800 meters was contested without the defending Olympic champion, Caster Semenya of South Africa, for the same reason.

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Below is a brief explanation of what DSD is, the rules that World Athletics has put in place, why the rules are controversial, and what DSD athletes have had to say about the issue.

What is DSD?

DSD stands for “differences of sexual development.” The World Athletics policies apply to women with 46, XY DSD—they have an X and Y chromosome in each cell (a typical male pattern) and male-range testosterone levels, as well as genitalia that is not typically male or female.

According to Children’s National Hospital, DSD is not as rare as most people assume and can affect about 1 in 100 newborns.

World Athletics has restricted women with DSD from competing in specific events on the track because, officials argue, that they have an unfair advantage in strength, muscle mass, and the increased testosterone levels improve oxygen-carrying capacity.

Why are DSD athletes banned from some women’s track and field events?

Under the policies, the athletes competing in the women’s division in the 400 meters to the one mile (events that require speed and endurance) are required to have testosterone levels below 5 nmol/L. It is possible for women with DSD to lower their testosterone levels through medication, like birth control or injections, or through surgery to remove internal testes (which can produce testosterone).

The World Medical Association has called the research that the policies are based on “weak” and called on physicians worldwide to refuse to implement measures to meet the World Athletics eligibility requirements.

“We have strong reservations about the ethical validity of these regulations,” Dr. Leonid Eidelman said. “They are based on weak evidence from a single study, which is currently being widely debated by the scientific community.”

When the rule was challenged in the Court of Arbitration for Sport (CAS), the arbitrators ruled that the research did not support the theory that DSD women gain an unfair advantage in the 1500 meters or mile and those distances should be reconsidered in the policy (they were never reconsidered, and women with DSD are not allowed to compete in those events).

The policies and research have also been criticized by many others as discriminatory and have been challenged by several athletes, most prominently by Semenya, who took her case to Switzerland’s supreme court. Her appeal was dismissed in 2020.

“I am very disappointed by this rule, but refuse to let World Athletics drug me or stop me from being who I am,” Semenya said in September 2020. “Excluding female athletes or endangering our health solely because of our natural abilities puts World Athletics on the wrong side of history.”

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Sebastian Coe, president of World Athletics, has stated: “The revised rules are not about cheating—no athlete with DSD has cheated—they are about leveling the playing field to ensure fair and meaningful competition.”

CAS agreed, ruling that the policies don’t infringe on athlete rights.

“The majority of the panel found that, on the basis of evidence submitted by the parties, such discrimination is a necessary, reasonable, and proportionate means of achieving the [World Athletics’] aim of preserving the integrity of female athletics in the restricted events.”

What do athletes with DSD say?

Semenya, who attempted to qualify for the Tokyo Games in the 5,000 meters but was unsuccessful, has framed it as a discrimination and human rights issue. After the Swiss court dismissed her case she said, “I will continue to fight for the human rights of female athletes, both on the track and off the track, until we can all run free the way we were born. I know what is right and will do all I can to protect basic human rights, for young girls everywhere.”

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At the 2021 Olympics, Mboma ran a new world record for woman under 20 years old, 21.81 seconds, although her favored event is the 400 meters, which she was banned from competing in. In Tokyo, she was asked by reporters how she felt about not being able to race the 400. She declined to comment, but said she was happy with her silver in the 200. “I just keep my head down and concentrate on the 200 meters. I got a medal.”

Francine Niyonsaba of Burundi was the silver medalist in the 800 meters in Rio, but was ineligible to compete in the event in Tokyo. She raced the 5,000 meters instead at the 2021 Games, but was disqualified in the semifinal for stepping inside the rail. She shares Semenya’s opinion that the policies are discriminatory.

“For sure, I didn’t choose to be born like this,” she said after Rio, adding, “I will keep my passion. I love running and I will not stop running.”