A Study Backing Caster Semenya’s Track Ban Was Seriously Flawed

Even before the study's forthcoming correction, many scientists agreed that the research was dubious.
Photo by Matthias Hangst, via Getty Images. 

The researchers of a study used to justify the disqualification of Olympic gold medalist Caster Semenya are expected to issue a correction that casts further suspicion on the decision to ban the athlete unless she medically alters her body.

In April 2018, the International Association of Athletics Federations (IAAF) announced a new rule targeting women and intersex athletes with testosterone levels of 5 nmol/L and above that requires them to take medication to lower their naturally occurring testosterone levels if they wish to compete. The rule, however, only applies to runners competing in the 400, 800, and 1500 meter races, leading many to assume that the regulation targeted Semenya.


For a decade, the IAAF has subjected the 28-year-old South African athlete to invasive “sex verification” tests and often denied her the right to compete. Most recently, Semenya has been barred from competing this fall at the IAAF World Championships over the regulation, and may miss out on her third Olympic games in 2020 if the decision is not ultimately overturned. In that time, the IAAF has been accused of racism and peddling faulty science in relation to Semenya’s case. Now, a reportedly massive new correction in one of the research papers used to support the IAAF’s new testosterone rule, which was obtained by correction-monitoring website Retraction Watch, is calling the IAAF’s scientific integrity back into question. The reported forthcoming correction has not yet been published in the journal Clinical Endocrinology, where the initial study appeared.

The original study, led by U.S. Anti-Doping Agency board member Richard Clark, initially concluded that there is no overlap in testosterone levels between cisgender men and women, and that intersex people’s levels of testosterone only ever overlap with cis men. The correction language published by Retraction Watch, however, shows that at least one intersex variation overlaps with testosterone ranges of both cis men and women. According to Roger Pielke Jr., professor and director of the Sports Governance Center at the University of Colorado Boulder, “the correction completely reverses the significance of the analysis.” VICE reached out to Clark for comment but did not hear back.


The study has been severely criticized by experts in the field, including Pielke and bioethicist Katrina Karkazis at Yale University. Karkazis points out that the study uses the terms “healthy” and “normal” to refer to non-intersex men and women. “It’s a convenient construct that they use to exclude from the sample women that they themselves are deeming are unhealthy. They’re construing their [DSD] diagnoses as indicating ill health and abnormality.”

Though Pielke put pressure on the researchers behind the paper to issue the correction, both he and Karkazis agree that the motivations behind the Semenya ruling are not based in science. “There is no valid scientific basis for the regulations,” said Pielke. “This has been shown over and over, and at this point would seem to be beyond dispute.”

Karkazis said she believes that the Semenya ruling has everything to do with a cultural misunderstanding of sex and testosterone perpetuated by policymakers in the sports world, which differs significantly from the scientific understanding of these two factors.

“Policymakers have long argued that the [testosterone] levels don’t overlap and other scientists have produced their own studies saying that they do,” says Karkazis, co-author of Testosterone: An Unauthorized Biography due out this fall. “If you talk to people in the sports science world, the vast majority will say yes [they do overlap].”


Because Pielke and Karkazis assert that the IAAF has never been concerned with science when it comes to this issue, they do not expect the corrections to influence the Semenya case. “Sports organizations have not been the greatest champions of scientific integrity,” said Pielke. “This is too bad, because evidence and science matter on this issue.”

Still, Clark’s study is not the only paper that was used to justify the ruling against Caster Semenya. One heavily-criticized study, which was commissioned and funded by the IAAF and the World Anti-Doping Agency, concluded that women with high testosterone have a “significant competitive advantage” over those with lower testosterone.

If not for the IAAF’s new ruling on testosterone levels, Semenya would be competing in the 2019 World Athletics Championships in October. She is currently in the middle of her second attempt to appeal the ruling in which this correction could be helpful if and only if the IAAF decides to listen to the scientific consensus on sex and testosterone.

VICE’s request for comment from the IAAF was not returned.

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