What You Need to Know From the 163-Page Caster Semenya vs. IAAF CAS Decision

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By Amby Burfoot, Guest Column
June 19, 2019

Yesterday, seven weeks after issuing its ruling in Semenya vs. IAAF, the Court of Arbitration for Sport released the full 163-page decision to the public. That news is not notable for the big picture, but for the telling details here and there. We already knew that Caster Semenya lost a 2-1 split decision, first announced on May 1. A “majority” of the three-judge panel agreed that the IAAF’s XY DSD regulation is necessary, reasonable, and proportionate. Under this ruling, Semenya and other XY DSD athletes in a narrow range of events (from 400 meters to the mile) will have to take testosterone-lowering drugs if they wish to continue competing in their preferred events.

(LetsRun has covered Semenya and the CAS trial at length elsewhere. For a detailed explanation of the situation, check out these two pieces LRC The Whole World Is Watching: Caster Semenya vs IAAF  LRC What No One Is Telling You About Caster Semenya: She Has XY Chromosomes)

However, we had not previously heard about direct testimony from Semenya herself or from the large group of experts assembled from both sides. There’s also a smidgeon of new, unpublished science in the CAS review, as well as a peek into the issues the CAS judges found most troublesome.

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Of course, we can’t forget that the game isn’t over. Semenya has appealed the CAS decision to the Swiss Federal Tribunal, which suspended the IAAF’s hyperandrogenism rules and gave the IAAF until June 25 to respond to its decision. This latest suspension of the rules — which apply only to Semenya, and not other XY DSD athletes — could last for some time. The Swiss Tribunal is likely to assemble a new group of judges to evaluate Semenya’s objections and, eventually, issue a ruling. This is likely to take another four to six months. Semenya plans to run the 800 meters at the next Diamond League meeting, the Prefontaine Classic at Stanford on June 30, and on Tuesday meet director Tom Jordan said that he was “happy to comply” with her request.

There’s no way to do a simple summary of a complex, 163-page decision, which you can read in full here. But here’s what I found most interesting, in no particular order, in the just-published CAS decision.

Semenya’s Testimony

According to the CAS summary, Semenya testified that various IAAF testosterone regulations have caused her “immense pain and suffering” and the new XY DSD rules feel like they were “created because of me.” When first told to lower her testosterone in 2009, Semenya said: “It was an order which I had no choice but to comply with.” The treatment she received from press, public, and IAAF was “atrocious and humiliating” and “continues to haunt me.”

Discussing her physical and mental state, and her performances while taking birth control pills to lower her testosterone from 2009 through 2015, Semenya said she suffered from constant nausea, stomach pain, fevers, weight gain, and a mental fog. She implied that the weight gain contributed to two years of knee injury in 2013 and 2014. After stopping the birth control pills (after CAS suspended the hyperandrogenism regulation in the Dutee Chand case), Semenya started feeling and running better in 2016.

The CAS panel was clearly moved and concerned by this personal report. More than 100 pages after reporting Semenya’s testimony, it accepted that “oral contraceptives can cause a range of unwanted side effects.” Nevertheless, it noted that millions of women worldwide take contraceptives (including Olympians wishing to avoid pregnancy), and that potential risks “do not outweigh” the need to provide fair competition for women.

Scientists, Scientists Everywhere

Semenya may still get to defend her 800m world title in Doha this year

Both sides presented a handful of “expert” sport science witnesses. They apparently didn’t call each other names, as CAS ultimately praised them for their “skill, diligence and courtesy.” But they sure did disagree on the question of testosterone and performance. More specifically, Semenya’s witnesses attacked the lack of a clear linkage between XY DSD athletes and any performance gain.

In particular, the experts fiercely debated the accuracy and meaning of several key scientific papers. Semenya’s people said, in effect: “This stuff is trash.” The IAAF people said, “It’s a bit preliminary, but the trends are unmistakable.” The CAS summary reads — if you can stand to read it all — like a he-said/she-said TV drama with excruciating biological and statistical detail. As a reader, it’s impossible to tell who’s telling “the truth.”

A majority of the CAS judges nonetheless found the IAAF position “compelling” and “causative.” They were also convinced by the “striking over-representation” of XY DSD individuals on the podium of major track events.

South African sports scientist Ross Tucker, well-known to many LetsRun readers, testified for Semenya. He basically argued that Usain Bolt has been more dominant in his event than Semenya in hers, and no one ever suggested putting the brakes on Bolt. Why Semenya?

An IAAF witness, professor Angelica Linden Hirschberg, a gynecologist from Sweden, reported on a new double-blind, randomized trial she recently completed. She gave 48 healthy young women either a testosterone cream or a placebo cream. Those receiving the T cream increased their VO2 max by 8.5 percent, and their anaerobic performance by 3.2 percent. This happened even though the women’s testosterone increased only to 4.3 nmol/L — that is, under the 5.0 limit allowed by the IAAF.

An apparently small number of athlete names were redacted from the scientific testimony to protect their privacy.

Legal Questions Re: Human Rights Law? Not In This Round

Semenya’s lawyers produced a handful of legal experts who claimed that the XY DSD regulation could be struck down in countries that have laws prohibiting sex discrimination. Arguing for the IAAF, Doriane Lambelet Coleman said that the IAAF is not beholden to existing human rights laws, though the situation is fluid. Coleman believes that XY DSD regulation is discrimination, yes, but necessary to maintain the “protected class” of women athletes. Otherwise, if athletes can compete according to their identity, XX women will inevitably lose to men who identify as women, including transgender men who do not lower their testosterone.

The CAS judges noted that they had received an amicus curiae brief in support of Semenya from a United Nations working group. CAS baldly termed this brief “not particularly useful.” Why not? Because no one doubts that there is some degree of discrimination here. What CAS found itself wrestling with was not discrimination per se but rather the question of the “conflicting rights” of XY DSD women and XX women. Someone will face discrimination. Who ya gonna call?

In the end, CAS decided that the IAAF and various courts will have to hammer out the human rights question. CAS focused only on determining where the discrimination line should be drawn.

The Compliance Issue

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Late in the CAS hearing and late in the full report, the question of testosterone compliance appears almost out of nowhere. In other words, what if it’s not as easy to keep a 5.0-or-below testosterone level as IAAF would like it to be?

Apparently, when Semenya took contraceptives, her testosterone ranged from a low of 0.5 to a high of 7.85, still under the 10.0 limit in effect then. She reported that she dutifully took the pills as required. Several experts said that training changes, like peak hard periods and easy taper periods, could change testosterone levels, among other things.

The IAAF’s medical experts said they have treated many women with oral contraceptives without major health problems. However, much less is known about how the pills affect testosterone levels, including daily and weekly fluctuations. CAS stated: “The matters of compliance are clearly very important.” Translation: If it’s not as easy to maintain low T levels as IAAF has argued, then we’ve got a problem, because the XY DSD regulation might no longer be “reasonable and proportionate.”

IAAF had initially established a strict adherence to the 5.0 rule. On May 7, however, it amended the rule to allow for “temporary and inadvertent non-compliance.”

Athletic Gender? Sports Sex? Gonadal Biology?

The CAS panel apologized profusely for some of the language used in this case. Not that it was profane, in the normal sense. But that it might prove offensive to certain parties. Or, as the CAS panel phrased it: “It is difficult in this area concerning sex and gender to describe matters in a way that is not offensive to some.”

This is a reference to IAAF’s use of the phrase “biologically male” to describe individuals identified as women at birth, raised as women, and continuing to identify as women throughout life. Sometimes it morphs to “gonadal biology” (with testes, and producing sperm and male levels of testosterone), sometimes to the notion that a person can have an athletic gender or sports sex different from the gender/sex they occupy in all non-sports activities.

Semenya and her supporters particularly attack the “biological male” language for its potentially harmful psychological effects. The CAS judges said they didn’t need to resort to such language. They were only concerned with the question of “athletic advantage” beyond the level of fair competition.

And, again, they found the IAAF’s arguments and solution “necessary, reasonable, and proportionate.”


Amby Burfoot won the Boston Marathon in 1968, and has been writing about track and road races since 1978.


Previous Amby Burfoot Caster Semenya Articles on LRC:

April 22, 2019: The Whole World Is Watching: Caster Semenya vs IAAF Who gets to participate in female sport? The Court of Arbitration for Sport may have to decid

May 2, 2019: Guest Column by Amby Burfoot: Let Semenya run free … in the 1500  The 1968 Boston Marathon champ who wrote a 5,000+ word piece in support of the IAAF’s regulations regarding Caster Semenya says he felt “no joy” when he read the CAS decision yesterday, and is now actually hoping the IAAF lets Semenya run the 1500.

Other LRC Semenya Articles:
May 2, 2019: What No One Is Telling You About Caster Semenya: She Has XY Chromosomes
2014: LRC Guest Column from Joanna Harper: A Brief History of Intersex Athletes in Sport
2009: The LetsRun.com Youtube video interview of Semenya that has nearly a million page views as it was one of the first video interviews of Semenya (an excerpt of it appeared on Good Morning America):


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