Press Release07 May 2019

IAAF publishes briefing notes and Q&A on Female Eligibility Regulations


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Over the past six days the IAAF has answered questions on the decision by the Court of Arbitration for Sport to uphold its Eligibility Regulations for the Female Classification [Athletes with Differences of Sex Development] from more than 100 journalists. We have pulled together the 12 most asked and answered questions which we would like to share with all media outlets and all other parties and individuals who would like to understand more about the Regulations, why we introduced them and the impact of testosterone on performance, in particular, in the protected female classification.


Empowering girls and women through athletics is a core value of the IAAF and the sport and sits at the heart of what all of us in athletics believe the sport can offer to participants and to the world. Because of the effect of testosterone on the body from puberty onwards, men are bigger, stronger and faster on average than women. That is why the female classification is 'protected', and why individuals who identify as female but have a certain difference of sex development (DSD) (which means that they have the same advantages over women as men do over women) can pose a challenge to that protected category. This is why we introduced the eligibility regulation and why it must be defended: to ensure fair competition for all women.

The CAS has upheld that principle saying:  ‘The Panel found that the DSD Regulations are discriminatory but that, on the basis of the evidence submitted by the parties, such discrimination is a necessary, reasonable and proportionate means of achieving the legitimate objective of ensuring fair competition in female athletics in certain events and protecting the “protected class” of female athletes in those events’.  CAS released a six-page Executive Summary of the decision, which we recommend you read in full:

We noted the three concerns expressed by the CAS Panel as to the fairness of the implementation of the Regulations. The CAS Panel in the Chand case (CAS 2014/A/3759) found that the previous iteration of the regulations was administered with 'care and compassion' by the IAAF, and this will not change. As the Regulations expressly state, the IAAF will keep all practical matters of implementation under periodic review. Indeed, the IAAF has already addressed the CAS Panel's first concern by amending clause 3.15 to say that temporary and inadvertent non-compliance with the 5 nmol/L limit for serum testosterone will not have any adverse consequences under the Regulations.

The regulations will now come into effect. The new, final version of the Regulations with explanatory notes were published on 1 May 2019 (after the CAS decision was announced) and will come into effect on 8 May 2019.

IAAF Eligibility Regulations for the Female Classification [Athletes with Differences of Sex Development]

Explanatory Notes: IAAF Eligibility Regulations for the Female Classification

Top 12 questions and answers on the IAAF DSD Regulations:

1. Which athletes fall under the DSD regulations?

The DSD regulations only apply to individuals who are:

  • legally female (or intersex) and
  • who have one of a certain number of specified DSDs, which mean that they have:
    • male chromosomes (XY) not female chromosomes (XX)
    • testes not ovaries
    • circulating testosterone in the male range (7.7 to 29.4 nmol/L) not the (much lower) female range (0.06 to 1.68 nmol/L); and
    • the ability to make use of that testosterone circulating within their bodies (i.e., they are ‘androgen-sensitive’).


2. What do such athletes have to do to be eligible to compete in the female classification?

If they are competing below international level, they do not have to do anything. They can compete without restriction.

If they are competing at international level, in one of the affected events (track races between 400m and one mile in distance), they first have to lower the level of testosterone in their blood down to below 5 nmol/L (because that is the highest level that a healthy woman with ovaries would have) for a period of six months, and maintain it below that level while they continue to compete at international level in such events.

If they want to compete at international level in other events, again they can compete without restriction, i.e., without lowering their testosterone levels.

To lower their testosterone levels in this way, affected athletes can either (a) take a daily oral contraceptive pill; or (b) take a monthly injection of a GnrH agonist; or (c) have their testes surgically removed (a ‘gonadectomy’). It is their choice whether or not to have any treatment, and (if so) which treatment to have. In particular, the IAAF does not insist on surgery. The effects of the other two treatments are reversible if and when the athlete decides to stop treatment.

Importantly, lowering testosterone in one of these ways is the recognised ‘gender-affirming’ standard of care for any individual (athlete or not) who is 46 XY but has a female gender identity.

3. Why do the regulations only cover events between 400m to the mile?

Based on the science, the IAAF considers that 46 XY DSD athletes would have an advantage in all events based on their levels of testosterone in the male range. However, the evidence to date indicates that track events run over distances between 400m to one mile are where the most performance-enhancing benefits can be obtained from elevated levels of circulating testosterone, i.e., both from the extra strength and power derived from the increases in muscle mass and strength, and from the extra oxygen transfer and uptake derived from the increased haemoglobin in the blood. 

Therefore, taking a conservative approach, to allow DSD athletes to compete in the gender with which they identify as far as possible without restriction, the new Regulations only apply to track events between 400m and one mile (and only to international competitions). However, the revised Regulations expressly confirm that the IAAF Health & Science Department will keep this under review.  If future evidence or new scientific knowledge indicates that there is good justification to expand or narrow the number of events affected by the Regulations, it will propose such revisions to the IAAF Council. 

4. Will you remove the 1500m and mile from your regulations, as suggested by CAS?

No. The CAS asked us to consider whether to defer application of the restrictions to these two distances pending further experience. However, we believe there is enough evidence from the field across all the disciplines covered by our regulations, so the 1500m and the mile will remain included in the regulations.  We may have more data in relation to the 400m and 800m, but there is evidence relating to the longer distances, and it is also generally accepted that an elite 800m runner will also excel over 1500m and one mile. We will keep this and all other aspects of the regulations under careful review as we move forward. 

5. How will you administer the Regulations?

The Regulations contain detailed requirements for confidential assessment of any new cases that arise. As found in the Chand case, the IAAF's regulations are administered with 'care and compassion', and that will remain the case moving forward.

The most immediate requirement is that all 46 XY DSD athletes who would like to compete at the World Championships in Doha in September in the restricted events need to provide the IAAF medical team with their serum testosterone level (from analysis of a blood sample using a mass spectrometry-based method as described in the Regulations) by 8 May. The testosterone concentration obtained from this blood sample must be below 5 nmol/L and remain under this value as long as the athlete is seeking eligibility to compete in the female classification in a Restricted Event at International Competition.  We will treat each athlete individually with a combination of testing their medical team does and testing our medical team undertakes, including random testing.

Usually, under the Regulations, a DSD athlete must suppress her testosterone below 5 nmol/L for a continuous six month period before competing in the female classification in a Restricted Event at an International Competition.  As a special transitional provision to ensure the delay caused by the legal challenge to the Regulations does not prejudice 46 XY DSD athletes, the IAAF will accept that DSD athletes who comply with the 5 nmol/L limit starting on or before 8 May 2019 will be eligible for the IAAF World Championships Doha 2019, assuming they meet the other required Eligibility Conditions.

6. What is your response to the claims about the harmful side effects of taking the medication you recommend?

CAS accepted the evidence of experienced medical experts that a 46 XY DSD athlete can bring her levels of testosterone down to below 5 nmol/L by taking ordinary doses of oral contraceptives. It also accepted that this may have unwanted side effects, but these are not different in nature to those experienced by the many thousands if not millions of XX women who take oral contraceptives, and that such side effects can be minimised by indivisualising treatment.

In short, then, side effects are a risk of taking any medication.  Side effects of oral contraceptives may include sweating episodes and flushes, which are more likely if compliance to treatment is poor or inconsistent.  Any side effects should be managed by the athlete’s treating physician, who should also advise the athlete on consistent compliance with her treatment.

There are some effects of the medication that might be considered as or confused with 'side effects' but are in fact the desired effects of treatment to reduce testosterone levels. Those are effects like loss of muscle mass, reduction of haemoglobin concentration, and increase in fat mass.  For many 46 XY individuals with one of these DSDs and a female gender identity, such treatment is the recognised standard of care, and the medication helps to change their body to better reflect their chosen gender.

7. Why are you targeting one athlete / How big a problem is this in the sport?

Some commentators have suggested that the regulations were (and have always been) directed at an individual athlete. That is not true. The IAAF is bound by strict confidentiality and so simply cannot – and will not – disclose the number of other athletes affected, or the identities of those athletes.

We have seen in a decade and more of research that approximately 7.1 in every 1000 elite female athletes in our sport are DSD athletes with very high testosterone levels in the male range.  The majority of those athletes compete in the restricted events covered by the regulations. This frequency of DSD individuals in the elite athlete population is around 140 times higher than you will find in the general female population, and their presence on the podium is much more frequent even than this. The CAS accepted that this demonstrates, in statistical terms, that they have a significant performance advantage.

8. Why are you focused on testosterone rather than other genetic differences like leg length, height or arm span?

It is correct that elite sport celebrates and rewards genetic differences (height, wing span, fast twitch muscles, etc).

The only genetic difference that elite sport does not celebrate is the genetic difference between men (with male chromosomes, XY) and women (with female chromosomes, XX). That is because XY chromosomes produce testes (rather than ovaries), which produce testosterone in the typical male range (rather than testosterone in the – much lower – typical female range), which is what produces men’s bigger and stronger bones and muscles and higher haemoglobin levels, which gives them a massive performance advantage over women.

CAS accepted this, and therefore accepted that the main driver of the marked sex difference in sport performance (10-12% on average) is the physical advantages conferred by having testosterone levels in the male range (7.7 - 29.4 nmol/L in blood) rather than the normal female range (06 - 1.68 nmol/L). 

Everyone agrees there must be separate male and female competition categories precisely to ensure that this genetic difference (XY chromosomes producing testes and high testosterone levels rather than XX chromosomes producing ovaries and low testosterone levels) is not outcome-determinative.

We regulate 46 XY DSD athletes because they have that same genetic difference. If that genetic difference makes it unfair for men to compete against women, it also (obviously) makes it unfair for 46 XY women to compete against women. The 46 XY DSD athlete’s testes mean that she produces testosterone not in the female range (0.06 to 1.68 nmol/L) but instead in the male range (7.7 to 29.4 nmol/L). If a 46 XY DSD athlete's body can make use of the testosterone that it produces, then she has all the same advantages as a 46 XY man has over a 46 XX woman.

That conclusion is supported by our research and observation, which show such athletes possess a very clear performance advantage. Our research of more than a decade included testing all female athletes at the Daegu 2011 and Moscow 2013 World Championships. We have been able to study performances of athletes with elevated and supressed testosterone levels and have seen the difference in performance in long sprint and middle distance running events. This has informed our regulations.

9. There is a lot of comment that the research and data underlying the regulations is flawed. How robust is the research?

There are a lot of published papers by the IAAF medical team and many other experts in the field. These articles (all of them) are only a part of the basis for the Regulations. The other part are scientific observations from the field with a historical listing of the DSD cases in Athletics, as well as performance evolution in DSD athletes when unsuppressed/suppressed/unsuppressed. These last two important components were shared with CAS but are highly confidential as they include medical data that can identify individual athletes. All published papers have been peer-reviewed. For example, the 2017 Bermon & Garnier BJSM paper was criticised for its statistical approach. A new set of statistics were provided on a modified database (taking into account some of the criticisms raised). This can be found in the BJSM 2018 paper which confirms with a different statistical method the main findings of the 2017 paper. This is explained clearly in the 2018 paper and other criticisms of these papers are misplaced. CAS in its reasoned decision acknowledged that although not comprehensive (for obvious methodological reasons), the research used by the IAAF was valid and admissible. CAS decided that that research, along with the other published papers provided by the IAAF, and the evidence from the field mentioned above, was enough to establish that the elevated testosterone levels that 46 XY DSD athletes possess can create an ‘insuperable advantage’ over other female athletes who do not have a 46 XY DSD.

10. If a DSD athlete competed nationally without taking medication and broke the world record in restricted events, would it be ratified?

No, the world record would not be ratified. The Regulations clearly require a DSD athlete to comply with the regulations (and supress her testosterone) in order to be eligible to set a world record in a restricted event at a competition that is not an International Competition. See clauses 2.1 and 2.3 of the Regulations.

11. What happens if these regulations are challenged under the national laws of different countries?

We would defend any claim that was made in any national or international forum as we would any other challenge (including if necessary on jurisdictional grounds). These are international sporting regulations so need to have harmonised effect across the world. That is why the rules require disputes to be resolved at CAS. CAS is competent to rule on all legal claims, including human rights claims, and it did so in its recent ruling, in favour of the IAAF.

The CAS has found the discrimination in these regulations (treating 46 XY DSD women differently from other women) to be justified because they are a necessary, reasonable and proportionate means of achieving the legitimate objective of protecting fair competition in the female classification. In short, it found that in this context ‘biological reality trumps gender identity’. That ruling should be respected and enforced by the national courts.

12. The World Medical Association (WMA) has issued a statement advising physicians not to implement the IAAF regulations and calling for their withdrawal. What is your response?

We have written to the WMA and its Board Members to make it clear that our Regulations are not predicated on a ‘single study’ but 15 years of observations and research from the field (as well as a number of peer-reviewed studies, many of which are listed in the explanatory notes to the Regulations, and are publicly available). We have also pointed out that in 46 XY DSD individuals, reducing serum testosterone to female levels by using a contraceptive pill (or other means) is the recognised standard of care for 46 XY DSD individuals with a female gender identity (whether those individuals are athletes, or not). These medications are gender-affirming. We have asked that our letter which can be found here is circulated to its members so they are aware of the information we have provided. We encourage all interested parties to read the regulations and the explanatory notes available on the IAAF website.

IAAF and human rights position 

The IAAF is not a public authority, exercising state powers, but rather a private body exercising private (contractual) powers. Therefore, it is not subject to human rights instruments such as the Universal Declaration of Human Rights or the European Convention on Human Rights.

However, the IAAF has itself committed (in Article 4 of the IAAF Constitution) to equal treatment and non-discrimination in the sport, whether on grounds of 'gender, race, religious or political views or any other irrelevant factor', and it does not shrink from that commitment in any respect.

In fact, it is that commitment to equal treatment that mandates provision of a female-only competition category, on the basis that the biological differences between the sexes mean this is the only way to guarantee female athletes an equal chance to excel and to secure the social and other goods that elite sport can offer. Anti-discrimination laws in Australia, the US and the UK recognise the need for this positive discrimination in favour of biological females on the basis of biological sex traits, and so expressly permit this female 'set-aside' in sport, and do not allow those excluded from the category to argue this is unlawful.

Athletes and Member Federations are bound by clause 5 of the DSD Regulations to resolve any dispute arising in connection with the DSD Regulations – and in particular 'the validity, legality and/or proper interpretation or application' of the DSD Regulations – before the Court of Arbitration for Sport (and not in any other forum). States, individuals or other entities are entitled to commence legal proceedings in any forum they choose, but that forum may or may not have jurisdiction to hear the case.

Human rights is an umbrella term for a wide array of rights that it is broadly agreed all humans inherently possess. But that does not mean that those rights are absolute, inviolable or sacrosanct. As an example, and as in this case, a right against discrimination or unequal treatment is not absolute: discrimination or unequal treatment may still be lawful, if the rule/policy is a necessary and proportionate means of achieving a legitimate objective. In this case, the CAS Panel found that the DSD Regulations were a necessary, reasonable and proportionate means of achieving the IAAF's legitimate objective of fair and meaningful competition in female athletics.

Further reading