"Mankind has always feared what it doesn't understand" - Magneto


This story has its origins in 2014 when Indian athlete, Dutee Chand ("Dutee"), initiated proceedings before the Court of Arbitration for Sports ("CAS") to challenge the IAAF Regulations Governing Eligibility of Females with Hyperandrogenism to Compete in Women's Competition ("Hyperandrogenism Regulations").

The Hyperandrogenism Regulations were introduced by the International Athletics Association Federation ("IAAF") in 2011 to limit the participation of female athletes with high androgen levels (a group of hormones) in female categories. The most well-known androgen is testosterone which has been shown to have a direct effect on athletic performance. The Hyperandrogenism Regulations set the maximum testosterone limit for females with hyperandrogenism at 10 nmol/L. This was well above the maximum testosterone level in the female population and slightly above the minimum level in the male population.

With the enforcement of the Hyperandrogenism Regulations, Dutee was effectively banned from competing in the female categories of athletic events due to the high testosterone levels in her body. Dutee initiated her challenge after being dropped from India's 2014 Commonwealth Games squad.

In July 2015, the CAS delivered an Interim Award partially upholding Dutee's challenge and suspending the Hyperandrogenism Regulations (CAS 2014/A/3759 Dutee Chand v AFI & IAAF). In rendering the interim award, the CAS determined that the testosterone hormone was the primary cause for the increase in lean body mass in males at puberty, which provided an advantage to male athletes over female athletes. A prime example of this advantage was showcased in the 1998 event themed 'Battle of the Sexes' where Karsten Braasch (ranked no. 203 at the material time) defeated both the Williams sisters in tennis matches.

Despite this, the Panel which heard Dutee's challenge was not satisfied as to the degree of that advantage granted to the athlete and declined to validate the Hyperandrogenism Regulations. The IAAF was given the opportunity to provide further evidence to validate the Hyperandrogenism Regulations in particular, as to the actual degree of athletic performance advantage sustained by hyperandrogenic female athletes by reason of their high levels of testosterone.

Three years later, in March 2018, the IAAF informed the CAS that it intended to withdraw the Hyperandrogenism Regulations and would not be providing any further evidence. That same year, Dutee went on to win two silver medals in the 2018 Asian Games.


Just a month thereafter, the athletics world was caught in what must have felt to be a déjà vu moment. The IAAF now sought to introduce the IAAF's Eligibility Regulations for the Female Classification (Athletes with Differences of Sex Development) ("DSD Regulations"). According to the United Kingdom's National Health System, DSD "is a group of rare conditions involving genes, hormones and reproductive organs, including genitals. It means a person's sex development is different to most other people's."

The DSD Regulations were a slightly more nuanced restriction against female athletes, governing the eligibility of females with certain differences of sex development to participate in the female categories of eight athletic events ("Restricted Events").

The impact of the DSD Regulations was limited only to female athletes with "46 XY DSD", namely conditions where the affected individual has XY chromosomes and therefore had the capability to produce testosterone levels well into the male range. Under the DSD Regulations, athletes with 46 XY DSD who have a natural testosterone level of above 5 nmol/L (1/2 of that permitted under the Hyperandrogenism Regulations), and who experience a "material androgenizing effect" (able to make use of the androgen and higher testosterone levels in the bodies) would be required to reduce their natural testosterone level to below 5nmol/L and to maintain that reduced level for a continuous period of at least six months in order to be eligible to compete in a Restricted Event at an International Competition. Thereafter, the said female athlete must maintain her blood testosterone level below five (5) nmol/L continuously (i.e. whether she is in competition or out of competition) for so long as she wishes to remain eligible. The standard of 5nmol/L was set because the IAAF claimed it to be the highest level that a healthy female with ovaries would have.

The DSD Regulations came into force on 1 November 2018. In implementing the DSD Regulations, the IAAF chief, Sebastian Coe, was quoted as saying "[t]he revised rules are not about cheating, no athlete with a DSD has cheated, they are about levelling the playing field to ensure fair and meaningful competition in the sport of athletics where success is determined by talent, dedication and hard work rather than other contributing factors".


Prior to the coming into force of the DSD Regulations, Caster Semenya ("Semenya") and the Athletics South Africa ("ASA") (collectively "Claimants") initiated proceedings before the CAS to challenge the validity of the DSD Regulations. Semenya was a regular participant in the Restricted Events, specifically the 400m, 800m and 1500m races. Semenya is perhaps most famously known for her back to back gold medals for the 800m race in the London Olympics 2012 and the Rio Olympics 2016.

The Claimants took the position that the DSD Regulations were unfairly discriminative against athletes on the basis of sex and/or gender because they only applied to female athletes, and specifically to female athletes having certain physiological traits. They also argued that the DSD Regulations lacked a sound scientific basis; was unnecessary to ensure fair competition within the female category; and was likely to cause grave, unjustifiable and irreparable harm to affected female athletes.

Hence, the Claimants sought an award from the CAS declaring the DSD Regulations unlawful on the basis that they were unfairly discriminatory, arbitrary and disproportionate. The Claimants submitted that the DSD Regulations violated, inter alia, the IAAF Constitution, the Olympic Charter, as well as universally recognised fundamental human rights.

The IAAF responded that the DSD Regulations were based on the best available science; did not discriminate on the basis of any protected characteristic; and was a necessary, reasonable and proportionate means of pursing the legitimate aim of safeguarding fair competition and protecting the ability of female athletes to compete on a level playing field.

With the battle lines drawn, the arbitral proceedings took place over five days during the winter of February 2019 in Lausanne, Switzerland, where various experts testified before the CAS Panel, including specialists in gynaecology and andrology; genetic, endocrinology and pharmacology; medical ethics; and sports performance.


On 30 April 2019, the CAS delivered its Award and, by a 2:1 majority, dismissed the Claimants' appeal. At the outset, the CAS recognised that not only did the dispute involve a complex collision of scientific, ethical and legal conundrums, but it also set against each other two incompatible, competing rights. On the one hand, was the right of every athlete to compete in sport, to have their legal sex and gender identity respected, and to be free from any form of discrimination. On the other, was the specific right of female athletes, accepted to be relevantly biologically disadvantaged compared to male athletes, to compete against other female athletes and to achieve the benefits of athletic success. This was in light of the fact that there was no challenge raised in these proceedings against the division of male and female athletes into different categories of sport.

The CAS distilled its reasoning for dismissing Semenya's challenge into three key areas:-


The CAS accepted that, on the face of it, the DSD Regulations were discriminatory as they imposed differential treatment based on protected characteristics. This finding was premised on two grounds:

(i) Legal sex: The DSD Regulations targeted a subset of the female/intersex athlete population without imposing an equivalent restriction on male athletes; and

(ii) Innate biological characteristics: The DSD Regulations targeted a group of individuals who have certain immutable biological characteristics, which do not apply to individual who do not have those characteristics.

Despite this, the CAS recognised that a rule that imposes differential treatment on the basis of a particular protected characteristic is valid if it is a necessary, reasonable and proportionate means of attaining a legitimate objective. This is similar to affirmative action which governs the economic policies of many nations.


This is where the members of the Panel first diverged, with the majority of the members of the Panel concluding that the IAAF had succeeded in establishing the necessity requirement.

As its starting point, the CAS gave due recognition to the age-old tradition of having separate categories for male and female competition. It was therefore left to be determined what was an objective, fair and effective means of determining which individuals could participate in those separate and distinct categories.

Looking behind this age-old tradition, the CAS accepted that it was a distinction that had been recognised due to biological attributes as opposed to mere legal status. In essence, it was to protect a class of individuals (females) who lack certain insuperable performance advantages from competing against those individuals who possessed those advantages (male). After all, the fun and thrill of competition is dampened if the competitors felt that no matter how hard they tried, they would definitely lose every time they stepped on the track because there was one competitor who had an advantageous biological trait which the other competitors could never possess.

Recognising the reasoning behind having the two separate categories meant that the classification of individuals into those two categories could not necessarily be drawn so cleanly based solely on legal sex. While in most cases it would be safe to draw this boundary, natural human biology does not map perfectly onto legal status and gender identity. After all, that was the very occurrence which had brought parties before the CAS.

Given the reason behind the necessity to organise separate male and female categories for competitive athletics, the majority of the Panel found that it would be legitimate to regulate the right to participate in the female category by reference to biological factors instead of legal status alone in order to ensure fair competition. This is especially, as espoused by the IAAF, as the singular factor that was not equally available to men and women, and which was the primary driver of the difference in sports performance between them, was the exposure to adult male level endogenous testosterone. Therefore, it would go against the very purpose of having separate categories for competitive athletes if individuals who possessed the testosterone-derived advantage were allowed to participate in the female category.

Having considered the expert evidence, the majority of the Panel ultimately accepted that the IAAF had discharged its burden of establishing that the DSD Regulations were necessary to maintain fair competition in female athletics. It had been shown that androgen sensitive female athletes with 46 XY DSD would enjoy a significant, and often determinative, advantage over other female athletes; an advantage which was attributable to their exposure to levels of circulating testosterone far exceeding the normal adult female range. The purpose of the DSD Regulations were therefore to ensure that female athletes who did not enjoy this significant performance advantage would not always be starting off with a handicap when stepping on the track.


The majority of the Panel went on to conclude that the DSD Regulations were reasonable and proportionate. This was especially as the DSD Regulations envisaged that female athletes could control their testosterone levels through conventional oral contraceptives without requiring surgical intervention.

However, the CAS did highlight some serious concerns it had over the practical implementation of the DSD Regulations. This included the potential difficulty for an athlete to comply with the requirements under the DSD Regulations, in particular the inability to consistently maintain a natural testosterone level below 5 nmol/L. In light of these concerns, the CAS left the door open for future challenges against the DSD Regulations; recognising that on implementation and with experience, certain evidence-backed facts may surface to affect the overall proportionality of the DSD Regulations thereby requiring the DSD Regulations to be amended and/or the category of Restricted Events to be reconsidered in order to ensure the fairness of the DSD Regulations.


Following the issuance of the CAS Award, Semenya took her case to the Swiss Federal Supreme Court who, on 31 May 2019, ordered the IAAF to suspend the implementation of the DSD Regulations pending Semenya's appeal against the CAS Award.

However, on 31 July 2019, the Swiss Federal Supreme Court reversed its previous ruling and stated that the DSD Regulations were once again applicable to Semenya. This resulted in Semenya being forced to miss the 2019 World Athletics Championships while continuing her appeal against the CAS Award.

Denied entry into her preferred world of athletics, Semenya took up a new sport by joining the South African Women Football League. Never one to shy away from a challenge, Semenya has since said that she would attempt to qualify for the 200m event (which is not a Restricted Event) in the Tokyo Olympics 2020 pending her appeal against the CAS Award.


The CAS Award has far reaching consequences. Semenya is not the only one who was affected by the DSD Regulations. Poignantly, her fellow 800m event podium finishers at the Rio Olympics 2016, Francine Niyonsaba (Burundi) and Margaret Wambui (Kenya) are also affected.

When the CAS Award was published, Semenya publicly stated that she knew "that the IAAF's regulations have always targeted me specifically" and "[f]or a decade the IAAF has tried to slow me down, but this has actually made me stronger. The decision of the [CAS] will not hold me back. I will once again rise above and continue to inspire young women and athletes in South Africa and around the world."

Commenting on the DSD Regulations, Dutee has been quoted as saying "[t]he rule is very wrong. Hyperandrogenism is natural, God-given. We were born this way, we have not done anything to our body to change it. So what can we do about it? How can we change it?" Dutee is not affected by the DSD Regulations as she participates in the 100m and 200m events, which are not classified as Restricted Events.

While an athlete can comply with the DSD Regulations by either taking medication, having a monthly injection, or having their testes surgically removed in order to reduce their blood testosterone level, the question that has to be asked is whether athletes should be discriminated against and forced to turn to medical alternatives in order to change the way they were born. This is especially given the increased focus of the sports world to have their sportsmen and sportswomen move further and further away from drugs.

Ultimately, the issue comes down to a question as to whether athletes, male or female, should be respected and allowed to compete based purely on their talents and abilities, whether obtained through nature and nurture.

"Mutation: it is the key to our evolution. It has enabled us to evolve from a single-celled organism into the dominant species on the planet. This process is slow, and normally taking thousands and thousands of years. But every few hundred millennia, evolution leaps forward." - Professor Xavier

16 JULY 2020

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.