As one might gather from the name, the Court of Arbitration for Sport, which is commonly known as CAS and is headquartered in Lausanne, Switzerland, focuses on sport issues. CAS was well out of its depth, therefore, when it announced a decision this past April 30 in effect defining who is female. That decision is starting to unravel, however. The Federal Supreme Court of Switzerland on June 13 provisionally suspended it pending a final decision by the Swiss Court, and the CAS decision is unlikely to survive that suspension.

The CAS decision involved the current Olympic gold medalist in the 800-meter run, Caster Semenya of South Africa—I participated in this proceeding as an expert witness for Semenya. She has higher-than-average naturally-produced testosterone, which, the CAS held, violated regulations of the International Association of Athletics Federations, commonly known as the IAAF, prohibiting her from competing in middle-distance races like the 800 meter unless she takes hormones that reduce testosterone. CAS’s upholding of the IAAF’s “Eligibility Regulations for the Female Classification (Athletes with Differences of Sex Development)” is fatally flawed for several reasons.

First, the idea that someone would have to take controlled substances in order to compete athletically is shocking on its face. Since East Germany required its athletes to take drugs in order to compete, no civilized country has done that.

Even if naturally produced testosterone gave an individual a competitive advantage—something on which there is no scientific consensus—that is not a reason to ban that individual from competition. Virtually every world-class athlete has some genetic advantage, or else they would not be world-class athletes.

Second, the Court of Arbitration for Sport is a court in name only. In actuality, it is a private arbitration body, not a court of law. The idea that a private body could make such an important worldwide decision on the definition of a woman is absurd. CAS simply should have made it clear in its decision that a sporting organization like the IAAF does not have the competence to regulate who is a woman.

The IAAF claimed when it announced its regulations that the regulations are not “intended as any kind of judgment on or questioning of the sex or gender identity of any athlete.” This is clearly doubletalk: Athletes like Caster Semenya, who was born as female, who was brought up as female, and who is legally considered by her country as female, are not permitted by the IAAF regulations to compete as females unless they alter their natural selves with performance-reducing drugs. That is clearly a decision that, according to the IAAF and CAS, Caster Semenya is not female. Unfortunately, that decision is all-too-consistent with a degrading statement about Caster Semenya attributed to the secretary general of the IAAF in 2009: “It is clear that she is a woman but maybe not 100%.”

Third, an authentic court of law, like the Swiss appellate court that is now reviewing the CAS decision and has provisionally suspended it, is constrained by public policy. CAS, a private arbitration body, did not reveal in its executive summary of the decision which body of law, if any, it is applying. Indeed, if the parties agree, the CAS Code permits the CAS to decide cases based on no law at all, but rather “ex aequo et bono” (according to the right and good).

Not knowing what law, if any, has been applied in this case is a particular problem, because, unlike what a court of law would have done, the CAS has not yet released to the public what its May 1 press release said was a 165-page decision. All that has been released to the public is the short executive summary referenced above.

That summary is completely conclusory, stating that, although the IAAF regulations are discriminatory, the requirement that athletes like Caster Semenya take hormones is a “necessary, reasonable and proportionate means of achieving the IAAF’s aim of preserving the integrity of female athletics.” There is no indication of a body of law or the public policy of a country that supports this conclusion. It appears to have been created out of thin air by two private individuals, because even one of the three arbitrators did not vote for it.

Although it may be appropriate for a private body like CAS to decide purely sporting issues, it is not at all appropriate for CAS to be deciding major, controversial social issues like what defines a female. Apparently the Swiss Federal Tribunal recognized the presumptuousness of CAS when the Swiss court provisionally suspended the CAS decision. I fully expect that the Swiss court’s decision will become its final judgment.