Caster Semenya v. IAAF

Just trying to make sense of this decade-long shitshow… (arguments welcome 🤝)

7 min readJul 5, 2020
Caster Semenya. Gold Coast Common Wealth Games 2018. Cameron Spencer/Getty Images

Humans like their sex categories neat, but nature doesn’t care. Nature doesn’t actually have a line between the sexes. If we want a line, we have to draw it on nature.” — Alice Dreger

Key terms:

IAAF: International Association of Athletics Federations (renamed to World Athletics in 2019)

CAS: Court of Arbitration for Sport

DSD: Differences in Sex Development — basically, characteristics. This goes alongside chromosomes, e.g. XY DSDs. (‘disorders’ is unnecessary alienating medical terminology, imo, but whatever)

CAIS (a DSD): Complete androgen insensitivity syndrome — a child is genetically male (XY), but during puberty, the body resists androgens (hormone determining the development of characteristics), thus “has some or all of the physical traits of a woman, but the genetic makeup of a man”

Hyperandrogenism: “biological state of a person whose body naturally produces an exceptionally high level of androgens (such as testosterone) — a woman having excessive levels of T

Nmol/L: Nanomole per Litre — used to measure great quantities of small substances

Preface: Imo, intersex people have been subjected to unjustifiable “normalisation”, primarily, through the reinforcement of medical authority, usually at birth — to my knowledge (so forgive me), there is not enough evidence to support a medical consensus on how intersex people should exist, so medical intervention at birth in non-emergency circumstances is disgusting. And in some cases, like this one, instrumentalised for the benefit of others. Ultimately, these are the opinions of a forever-learning cisman lol, and you’d be served best by the experiences of an actual intersex person.

Let’s start in 2011:

Hyperandrogenism regulations (testosterone suppressing) introduced for women’s track — it’s here where Caster was first forced to take hormone suppressing drugs.

  • 2014: Dutee Chand (19 at the time; 100m) takes AFI (Athletics Federation of India) + IAAF to court
  • 2015: CAS gave an interim ruling suspending the regulations, in favour of Chand because the IAAF failed to present sufficient scientific evidence for the connection between enhanced testosterone levels (hyperandrogenism) and “a real competitive advantage” (532)) of “10%-12%” (526) — this will be important later on!

To reiterate, IAAF was told to quantify the magnitude of advantage derived from “enhanced levels of endogenous testosterone”, i.e. just provide actual scientific evidence within 2 years. Intuitively, ppl may assume ‘how tf doesn’t it give an advantage when its artificial counterpart is banned because it does?’, but natural testosterone is influenced by several outliers that the IAAF did not factor and makes such specific categorisation inherently faulty, imo.

JULY 2017:

IAAF comes back with (in-house conducted) research (by Bermon & Garnier) to justify hormone suppressing regulations for intersex athletes:

But this time, IAAF came back with new research accompanied by revised regulations instead of stronger evidence. Regulations only apply to individuals with male chromosomes (XY) + who are “legally female (or intersex) and who have one of a certain number of specified DSDs”. In other words, exempt: XX women with DSDs that elevate testosterone; not exempt: 46XY Women with DSDs elevating testosterone levels past the 5nmol/L threshold the IAAF deems is F enough to ‘protect’ them.

Yet, instead of the suspended testosterone limit (from 10nmol/L to 5), they introduced in 2011 applying to all female athletes, they now only wanted regulations to apply to track events between 400m and 1 Mile — basically Caster’s range, so it’s not outlandish to assume she’s being unfairly targeted.

  • Research measures: “In female athletes, samples were collected regardless of their menstrual status and phase.” Okay? *confused emoji* I dunno, seems like something kinda important to consider.
  • Research methodology: They observed 2127 female and male athletes at the 2011 & 2013 World Championships, specifically 21 female and 22 male track & field events.

Claims female athletes with hyperandrogenism in a handful of track & field events with hyperandrogenism only performed >4% (remember CAS asked for “10%-12%”) better than those with the lowest levels. The researchers said, “Our study design cannot provide evidence for causality between androgen levels and athletic performance, but can indicate associations between androgen concentrations and athletic performance.”

The IAAF’s new regulations were only supported by evidence in the female hammer throw (4.53%), pole vault (2.94%), 400m (2.73%), 400m hurdles (2.78%), and 800m (1.78%) — congrats, I guess — but not the 1500m/mile, which wasn’t even fucking tested. However, by their lowered standards, the hammer throw and pole vault still, ironically, remain exempt from the regulations even though that’s where hyperandrogenism had the biggest effect.

The study observed all types of athletes (including 46XY DSDs); only 5/21 events fit the IAAF’s agenda, while 16 invalidate their concept, but they still went ahead and deemed it justifiable enough for the discriminatory effect of the new regulations against female athletes like Caster.

And still, the IAAF disregarded outliers that do or possibly can contribute to testosterone construction and circulation, such as nutrition, training, lifestyle, and arguably even environment. I’m merely speculating: Fair to assume athletes are outliers on many genetic traits and not just T — which is being used here, primarily, because of its impact during puberty — so the impact of outliers in the development of T for them could potentially be substantial. Exclusion during hormonal research is argued to have a substantial impact on results, but it depends on what type. Some interesting info:; related:

JULY 2018:

It’s criticised by 3 independent researchers (Pielke, Tucker, & Boye):



Essentially, they found that performance data used in the study was “anomalous or inaccurate 17% to 33% of the time”… fucking wow, but not surprising

FEB 2019:

Updated criticism of 25% of the IAAF’s study that was provided by the authors:

  • Duplicated athletes: More than one time is included for an individual. In each of these instances, more than one time from the 2011 and 2013 World Championships is included for the same athlete.
  • Duplicated times: The same time is repeated once or more for an individual athlete, which is clearly a data error.
  • Phantom times: No athlete could be found with the reported time for the event.
  • The IAAF set itself up for problems by conducting research on performance effects associated with testosterone using in-house researchers.

The researchers even asked for the paper to be retracted because they thought it was that bad — IAAF ultimately ignored the request.

FEB 2019:

IAAF is said to have shifted to sex testing, they say they’re not.

MAY 2019:

CAS ruling:

  • CAS ruled in favour of the IAAF
  • Beginning at 68, it states she has 5-αlpha-reductase type 2 deficiency (5–ARD2 — a DSD) = biologically male — she has internal testes instead of ovaries; ‘Caster developed testes but not a penis (CAIS)’ — not to be conflated with specifically only having higher levels of testosterone, which Caster does have; ‘Caster is 46XY woman’— doesn’t necessarily = male tho

That same paragraph also makes note of the impact, or lack thereof, of dihydrotestosterone — a powerful androgen that’s banned by WADA — which 46XY 5-ARD2 females have an insufficient amount of to validate the argument they benefit from an advantage similar to anywhere close to that of their male counterparts regardless if they are hyperandrogenic/have elevated levels of testosterone… hence the classification of ‘female’!

Thus, when the IAAF determines that some 46 XY females should be in fact be considered biological males, it misrepresents basic biological understandings and deviates from the widely shared position of the international medical community, such as reflected in statements by the World Health Organization”, say Roger Pielke Jr. & Madeline Pape.

  • IAAF DSD rules validated — a significant contribution to their success is the (imo) deliberate conflation of intersex athletes (claiming Caster is 46XY DSD) with trans MTF athletes (see 285, 292, 397), using this case as a means to pre-emptively address a separate issue — even if they weren’t, it’s still disrespectful

CAS concluded, its role is to “determine whether the DSD regulations are necessary, reasonable and proportionate” and it “does not consider it necessary specifically to determine whether the IAAF’s invocation of the concept of a ‘male sport sex’ possessed by ‘biological males’ and a ‘female sport sex’ possessed by ‘biological females’ is valid and/or proper.

It’s fuckin ironic n stupid they’ve said this because the IAAF is basically establishing a new sex testing method, and the new rules are directly connected to the 2017 study, so CAS has, evidently, also shifted the fucking goalposts, ruling in favour of theory/concept — that this is a matter of ‘Females v. Males’, which was what the IAAF relied on — rather than in favour of evidence (or lack thereof) like it did with Chand in 2015, thus endorsing the IAAF’s new sex determination practices… ahhh, just like the good ol’ days.

So, the IAAF will make intersex athletes undergo unproven medical intervention under the guise of “fair play” after explicitly, also, shifting goalposts to fit its decade-long agenda. Initially, saying it was not seeking to establish new forms of sex testing, it has come full circle with even more stupidity and the validation of the highest court in sports for such, currently, unjustifiable (and thus unfair) practices.

Ultimately, like everyone, I believe that defending the line between Ms n Fs is necessary to protect the integrity of sports, namely, the space for F athletes, however, it requires substantial evidence to introduce such specific, discriminatory rules, and the science just isn’t fucking available here. It’s fucking bullshit, frankly.

Response to CAS ruling by Tucker:

JUNE 2019:

Caster files an appeal at the Swiss Federal Tribunal and the IAAF is told to suspend the implementation of the regulation via “a supervisional order”

JULY 2019:

Swiss court reverses and lifts suspension

MAR 2020:

Caster announces she’s switching to the 200m

17 August 2021:

World Athletics admit that the 2017 paper (by Bermon and Garnier) underpinning the DSD rules might be “misleading by implying a causal inference” and the evidence used was only “exploratory”

The correction also states: “To be explicit, there is no confirmatory evidence for causality in the observed relationships reported”.