ELIGIBILITY REGULATIONS FOR THE FEMALE CLASSIFICATION(ATHLETES WITH DIFFERENCES OF SEX DEVELOPMENT)EXPLANATORY NOTES/Q&A

What is the change?
In April 2018, the IAAF issued new Eligibility Regulations for the Female Classification (Athlete withDifferences of Sexual Development). These new Regulations, which were due to come into effect asfrom 1 November 2018, replaced the previous Regulations Governing Eligibility of Females with
Hyperandrogenism to Compete in Women's Competition, which no longer applied anywhere in the
sport. The new Regulations were stayed pending a legal challenge to their lawfulness before the
Court of Arbitration for Sport (CAS).
On 1 May 2019, the CAS Panel that heard the challenge upheld the Regulations. The IAAF hastherefore published version 2.0 of the Regulations on 1 May 2019, which will come into effect asfrom 8 May 2019.
Why has the IAAF issued these Regulations?
As the Court of Arbitration for Sport (‘CAS’) Panel recognised in Chand v IAAF & AFI (CAS2014/A/3759), men have significant advantages in size, strength and power over women, due inlarge part to men's much higher levels of circulating testosterone from puberty onwards. Because of
the impact that such advantages can have on sporting performance, it is generally accepted thatcompetition between male and female athletes would not be fair and meaningful, and would risk
discouraging women from participation in the sport.1 Therefore, in common with many othersports, the IAAF has created separate competition categories (or ‘classifications’) for male andfemale athletes.
As the CAS Panel also accepted, however, while biological sex is an umbrella term that includes
distinct aspects of chromosomal, gonadal, hormonal and phenotypic sex, each of which is fixed andall of which are usually aligned into the conventional male and female binary, some individuals havecongenital conditions that cause atypical development of their chromosomal, gonadal, and/or
anatomic sex (known as differences of sex development, or ‘DSDs’, and sometimes referred to as'intersex').2 Such individuals may have levels of circulating testosterone well above the normal
female range, into and even exceeding the normal male range.
The CAS Panel ruled that it is up to the IAAF to decide, based on a careful consideration of theavailable evidence (including the scientific evidence of the extent of the performance advantage thatsuch elevated testosterone levels confer), what conditions (if any) need to be placed on theparticipation of DSD athletes in the female classification in order to preserve fair and meaningfulcompetition in that classification.
Having gathered and analysed that evidence, the IAAF decided that the previous Hyperandrogenism
Regulations needed to be rewritten, to narrow their scope to certain track events, and to strengthen
the restrictions applicable to athletes with DSDs participating in those events. The result is these
new Regulations, which seek to facilitate the participation in the sport of athletes with DSDs on
terms that preserve fair and meaningful competition in the female classification.
1

There is a substantial (on average, 10‐12%) sex difference in athletic performance.

2

As a result, some national legal systems now recognise legal sexes other than simply male and female(for example, 'intersex', 'X', or 'other').
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ELIGIBILITY REGULATIONS FOR THE FEMALE CLASSIFICATION(ATHLETES WITH DIFFERENCES OF SEX DEVELOPMENT)EXPLANATORY NOTES/Q&A
What is the evidence on which these new Regulations are based?
Most females (including elite female athletes3) have low levels of testosterone circulating naturally
in their bodies (0.12 to 1.79 nmol/L in blood); while after puberty the normal male range is muchhigher (7.7 – 29.4 nmol/L). Absent a DSD or a tumour, no female would have serum levels of
testosterone of 5 nmol/L and above, but individuals with DSDs can have very high levels of natural
testosterone, extending into and even beyond the normal male range.4
There is a broad medical and scientific consensus that if these individuals are sensitive to androgens(i.e., they have properly‐functioning androgen receptors), such very high levels of natural
testosterone can increase their muscle mass and strength, as well as their levels of circulating
haemoglobin, and so significantly enhance their sporting potential.5
Experts consulted by the IAAF have gathered and reviewed all of the published evidence and data,
which indicates that increasing the level of circulating testosterone from the normal female range tothe normal male range leads to increased muscle mass and strength and higher haemoglobin levels.
In particular, increasing testosterone levels in women from 0.9 nmol/L to just 7.3 nmol/L increases
muscle mass by 4% and muscle strength by 12‐26%; while increasing it to 5, 7, 10 and 19 nmol/L
respectively increases circulating haemoglobin by 6.5%, 7.8%, 8.9% and 11% respectively. Taking all
available knowledge and data into account, the experts estimate that the ergogenic advantage in

3

See Bermon et al, Serum Androgen Levels in Elite Female Athletes, J Clin Endocrin Metab, doi:
10.1210/jc.2014‐1391
4

See Handelsman, Hirschberg and Bermon (2018), Circulating Testosterone as the Hormonal Basis of
Sex Differences in Athletic Performance, Endocrine Reviews, Volume 39, Issue 5, 1 October 2018, pp. 803–829.

5See, for example, Handelsman, Hirschberg and Bermon (2018), Circulating Testosterone as the
Hormonal Basis of Sex Differences in Athletic Performance, Endocrine Reviews, Volume 39, Issue 5, 1 October
2018, pp. 803–829; Auchus (2017) Endocrinology and Women’s Sports: The Diagnosis Matters, 80 LAW &CONTEMP. PROBS., no.4, 2017, p.127; Allen (2016) Hormonal eligibility criteria for 'includes females'
competition: a practical but problematic solution, Horm Res Paediatr 85:278–82; Bermon et al (2015), Women
with Hyperandrogenism in Elite Sports: Scientific and Ethical Rationales for Regulating, J Clin Endocrinol MetabJan 14:doi:jc.2014‐3603; Ritzén et al (2015), The regulations about eligibility for women withhyperandrogenism to compete in women's category are well founded. A rebuttal to the conclusions by Healy etal., Clin Endocrinol 82:307–8; Sanchez et al (2013), The New Policy on Hyperandrogenism in Elite Female
Athletes is not about "Sex Testing", J Sex Res, February, 50:112‐115; Wood & Stanton (2012), Testosterone andSport: Current Perspectives, Horm Behav January; 61:147‐155; Ballantyne et al (2012), Sex and gender issues incompetitive sports: investigation of a historical case leads to a new viewpoint, Br J Sports Med, 46:614‐617;
Gooren (2011), The significance of testosterone for fair participation of the female sex in competitive sports,
Asian Journal of Andrology 13, 653‐654; Hercher (2010), Gender Verification: A Term Whose Time Has Comeand Gone, J Genet Counsel, 19:551‐553; Handelsman and Gooren (2008), Hormones and sport, Asian Journal ofAndrology, 10, 348‐50; Hipkin (1992), The XY female in sport: the controversy continues, Br J Sp Med,
27:150156. Cf Healy et al (2014), Endocrine profiles in 693 elite athletes in the post‐competition setting,
Clinical Endocrinology, 81:294‐305; Sonksen et al (2014), Medical and Ethical Concerns Regarding Women with
Hyperandrogenism and Elite Sport, J Clin Endocrinol Metab:doi:10.1210/jc.2014‐3206; Sonksen (2016),
Determination and regulation of body composition in elite athletes, Br J Sports Med, 2016;0;1‐13;
doi:10.1136/bjsports‐2016‐096742. See also Huang and Basaria (2017), Do anabolic‐androgenic steroids have
performance‐enhancing effects in female athletes Mol Cell Endocrinol. 2018 Mar 15;464:56‐64.
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ELIGIBILITY REGULATIONS FOR THE FEMALE CLASSIFICATION(ATHLETES WITH DIFFERENCES OF SEX DEVELOPMENT)EXPLANATORY NOTES/Q&A
having circulating testosterone levels in the normal male range rather than in the normal female
range is greater than 9%.6
The significant over‐representation of DSD athletes in certain events, and their success in those
events, provides further indirect but strong corroboration of the above.7 In addition, the IAAF hasgathered observational data about the difference in performance levels of DSD athletes dependingon whether or not their testosterone levels are suppressed, including data showing that suppressionof the levels of circulating testosterone of three DSD athletes from 21‐25 nmol/L to below 2 nmol/Lcoincided with their performances decreasing by an average of 5.7%.8
This evidence shows clearly that (at least in certain events) DSD athletes with levels of circulating
testosterone in the normal male range have a very significant competitive advantage over female
athletes with testosterone levels in the normal female range, which justifies requiring DSD athletes
to reduce their testosterone levels down to the normal female range in order to compete in thefemale classification in such events.
What do these Regulations require?
The data indicate that the advantages conferred on certain DSD athletes have been of greatest
effect to date in middle distance track events. The Regulations therefore apply only to track events
run over distances between 400m to one mile (the Restricted Events) at International
Competitions.9
If a female athlete wishing to participate in a Restricted Event at an International Competition has a
DSD that results in levels of circulating testosterone greater than 5 nmol/L, and her androgen
receptors function properly, such that those elevated levels of circulating testosterone have a

6

Handelsman, Hirschberg and Bermon (2018), Circulating Testosterone as the Hormonal Basis of Sex
Differences in Athletic Performance, Endocrine Reviews, Volume 39, Issue 5, 1 October 2018, pp. 803–829.

7

Bermon et al (2014), Serum androgen levels in 1058 elite female athletes, J. Clin. Endocrinol. Metab.
99:4328‐4335. In addition, peer‐reviewed data from the IAAF World Championships in Daegu (2011) andMoscow (2013) indicate that women in the highest tertile (top 33%) of testosterone levels performed
significantly better than women in the bottom tertile (bottom 33%) in the following events: 400m hurdles(top tertile, with mean T concentration of 1.94 nmol/L, outperformed bottom tertile, with mean T
concentration of 0.43 nmol/L, by 3.13%; 400m (top tertile, with mean T concentration of 7.39 nmol/L,
outperformed bottom tertile, with mean T concentration of 0.40 nmol/L, by 1.50%; and 800m (top tertile, withmean T concentration of 3.28 nmol/L, outperformed bottom tertile, with mean T concentration of 0.39
nmol/L, by 1.60%): Bermon and Garnier (2017), Serum androgen levels and their relation to performance intrack and field: mass spectrometry results from 2127 observations in male and female elite athletes, Br J
Sports Med 2017;0:1‐7, additional material at http://bjsm.bmj.com/content/51/17/1309.

8

Bermon (2017), Androgens and athletic performance of elite female athletes, Curr Opin Endocrinol
Diabetes Obes 2017;24:246–51.
9Whereas the previous Hyperandrogenism Regulations applied not only to International Competitions,but also to all competitions held under the rules of an Area or member national federation, the newRegulations apply only to International Competitions. As a result, it will only impact on athletes competing at
the very highest levels of elite athletics. Those competing below those levels (e.g., in national‐levelcompetitions) will not be impacted at all by the new Regulations.
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ELIGIBILITY REGULATIONS FOR THE FEMALE CLASSIFICATION(ATHLETES WITH DIFFERENCES OF SEX DEVELOPMENT)EXPLANATORY NOTES/Q&A
material androgenising effect10 (a Relevant Athlete), she must reduce those levels down below 5
nmol/L for six months (e.g., by use of hormonal contraceptives) before competing in such events,and must maintain them below that level until she no longer wishes to participate in Restricted
Events at International Competitions.
No other measures are required. In particular, surgical anatomical changes are not required in any
circumstances (just as they were not required under the previous regulations).
Why do the new Regulations only apply to ‘Restricted Events’?
Based on the evidence referred to above, it appears that these events (track events run overdistances between 400m to one mile) are where the most performance‐enhancing benefits can beobtained from elevated levels of circulating testosterone, i.e., both from the extra strength andpower 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, the new Regulations only apply to such events.
However, the revised Regulations expressly confirm that the IAAF Health & Science Department willkeep this under review. If future evidence or new scientific knowledge indicates that there is goodjustification to expand or narrow the number of events affected by the Regulations, it will propose
such revisions to the IAAF Council.
Is the IAAF questioning the sex or gender identity of female athletes with DSDs?
No. These Regulations exist solely to ensure fair and meaningful competition within the female
classification, for the benefit of the broad class of female athletes. In no way are they intended as
any kind of judgement on or questioning of the sex or the gender identity of any athlete. To thecontrary, the IAAF regards it as essential to respect and preserve the dignity and privacy of athleteswith DSDs, and therefore it will continue to handle all cases arising under these Regulations in strict
confidence.
The new Regulations also include an express warning that anyone who breaches confidentiality, or
harasses or stigmatises an athlete, or infringes her dignity or her privacy, will be subject todisciplinary sanction under the IAAF Integrity Code. In particular, persecution or campaigns against
athletes simply on the basis that their experience does not conform to gender stereotypes areunacceptable.
What other protections are there for athletes with DSDs?

10

Some DSD athletes have natural mutations that make their androgen receptors completely or
partially insensitive to testosterone. If they are completely androgen‐insensitive, then the Regulations do not
apply to them. If they are partially androgen‐insensitive, the Regulations only apply to them if they are
sufficiently androgen‐sensitive that their elevated testosterone levels have a material androgenising effect. As
under the previous Regulations, this is to be assessed by an expert independent medical panel based on
physical evaluation and endocrine testing, but with the benefit of any doubt on the issue to be resolved infavour of the athlete (whereas under the previous Regulations the burden was stated to be on the athlete toprove that due to androgen resistance she derives no competitive advantage from her elevated testosterone
levels).
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ELIGIBILITY REGULATIONS FOR THE FEMALE CLASSIFICATION(ATHLETES WITH DIFFERENCES OF SEX DEVELOPMENT)EXPLANATORY NOTES/Q&A
The CAS Panel in Chand v. IAAF & AFI specifically noted that the Hyperandrogenism Regulations
were administered by the IAAF in confidence and with care and compassion, and that they could
benefit athletes by identifying underlying medical conditions that require urgent treatment. The
IAAF will maintain exactly the same approach under the new Regulations.
In particular, the new Regulations re‐affirm that only the IAAF Medical Manager may initiate an
investigation in relation to any athlete, and only on reasonable grounds based on information fromreliable sources, to avoid the risk of improper 'witch‐hunts' of athletes based merely on physicalappearance. In addition, to support the existing provisions requiring informed consent from theathlete at every stage of the process, a new provision has been included for the appointment of an
athlete ombudsman to assist the athlete in understanding the regulations and her options underthem.
Furthermore, any case arising under the revised Regulations will not be handled by the athlete's
national federation, but instead will be handled by the IAAF Medical Manager and the panel of
independent medical experts appointed by the IAAF (with the IAAF covering the costs). This will
avoid any risk of improper application of the Regulations at national level due to lack ofunderstanding/resources, as well as the risk of inconsistent application of the Regulations bydifferent national federations.
What if an athlete with a DSD does not wish to have to comply with the Regulations?
An athlete with a DSD who did not wish to have to comply with the Regulations would not be barredfrom competing in the sport. To the contrary, without suppressing her elevated levels of circulating
testosterone, she would still be entitled to compete:(1) in the female classification:a. at any competition that is not an International Competition: in any event, without
restriction; andb. at International Competitions: in any discipline other than track events between
400m and a mile; or(2) in the male classification: at any competition at any level, in any discipline, without
restriction; or(3) in any 'intersex' (or similar) classification that the event organiser may offer: at any
competition at any level, in any discipline, without restriction.
Why do the new Regulations not refer to athletes with hyperandrogenism?
It would be misleading to suggest that the Regulations apply to all female athletes withhyperandrogenism, because in normal medical parlance that would include women with polycystic
ovary syndrome (PCOS), but the levels of circulating testosterone of such athletes would be less than
5 nmol/L, and therefore they will not be covered by the new Regulations.
Why has the limit for circulating testosterone changed from 10 nmol/L to 5 nmol/L?
A rigorous review of the data has established that the normal female range of circulating
testosterone in serum is 0.12 to 1.79 nmol/L, and the normal male range is 7.7 to 29.4 nmol/L, while
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ELIGIBILITY REGULATIONS FOR THE FEMALE CLASSIFICATION(ATHLETES WITH DIFFERENCES OF SEX DEVELOPMENT)EXPLANATORY NOTES/Q&A
women with PCOS could have circulating testosterone as high as 4.8 nmol/L. Therefore, the only
female athletes competing with levels above 5 nmol/L would be intersex/DSD athletes, doped
athletes, and athletes with adrenal or ovarian tumours. In addition, (a) below 5 nmol/L, there islimited evidence of any material testosterone dose‐response; but (b) an increase in circulating
testosterone from normal female range up to between 5 and 10 nmol/L delivers a clear performanceadvantage (according to the studies, a 4.4% increase in muscle mass and a 12‐26% increase inmuscle strength, and a 7.8% increase in haemoglobin).11
Accordingly, if the Regulations are to do their job of protecting the level playing‐field in the female
classification, then the threshold needs to be 5 nmol/L, not 10 nmol/L.
Under the new Regulations, all measurements of circulating testosterone levels must be conductedby means of gas or liquid chromatography coupled with mass spectrometry using a validated
method.
Why is there now a six‐month period during which a Relevant Athlete must keep her testosterone
levels below 5 nmol/L before she may compete in Restricted Events at International
Competitions?
This requirement has been introduced in order to minimise any lingering advantages that a Relevant
Athlete may have from having previously had levels of circulating testosterone well above 5 nmol/L.
The normal life‐cycle of a red blood cell is about 120 days. Therefore, six months should be enoughto see a reduction in haemoglobin following the reduction in circulating testosterone, even if thebenefits of increased muscle mass and strength will likely endure to some extent beyond that.
The new Regulations will come into effect only from 8 May 2019. Therefore, female athletes with
DSDs are able to start demonstrating compliance with this requirement immediately should theywish to avoid having to stand down from competition once the Regulations come into effect.
Compliance with this requirement will be monitored by random testing, and any demonstrated non‐compliance will trigger a new ‘stand‐down’ period of six months, during which the athlete will not beable to compete in Restricted Events at International Competitions.
Will Relevant Athletes be eligible to compete at the IAAF World Athletics Championships, Doha2019?
One of the Eligibility Conditions at clause 2.3 of the Regulations requires a Relevant Athlete to
reduce her testosterone levels to below 5 nmol/L for a continuous period of at least six months prior
to competition in the female classification in a Restricted Event at an International Competition. Six
months from 8 May 2019 (the date that the new Regulations come into force) will expire after the2019 IAAF World Athletics Championships in Doha have taken place.
However, version 2.0 of the new Regulations contains a special transitional provision that has been
introduced by the IAAF to ensure that the delay in the Regulations coming into effect caused by thelegal challenge to the Regulations does not prejudice Relevant Athletes.

11

See Handelsman, Hirschberg and Bermon (2018), Circulating Testosterone as the Hormonal Basis of
Sex Differences in Athletic Performance, Endocrine Reviews, Volume 39, Issue 5, 1 October 2018, pp. 803–829.
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ELIGIBILITY REGULATIONS FOR THE FEMALE CLASSIFICATION(ATHLETES WITH DIFFERENCES OF SEX DEVELOPMENT)EXPLANATORY NOTES/Q&A
The special transitional provision, at clause 2.3(b), states that a Relevant Athlete who reduces her
blood testosterone to below five (5) nmol/L for a continuous period starting from 8 May 2019 to 28
September 2019 will be deemed to have met this eligibility condition to compete in the female
classification in a Restricted Event at the IAAF World Athletics Championships, Doha 2019.
All elite athletes have natural genetic and/or biological advantages (e.g., height, lung capacity,etc). The IAAF does not stop them reaping the benefits of those advantages, so why deny DSD
athletes the benefit of their natural levels of circulating testosterone?
The IAAF divides competition into male and female classifications because male athletes have clear
performance advantages in terms of size, strength and power, as a result (in particular) of increased
lean body mass and increased serum haemoglobin, which in turn is due mainly to the fact that,starting from puberty, they produce 10‐30 times more testosterone than women. As noted above,
the CAS has found that this difference justifies protecting female athletes from competition frommale athletes.
Where a female athlete has a DSD that gives her levels of circulating testosterone in the male range,and she is sufficiently androgen‐sensitive for those levels to have a material androgenising effect,e.g., increasing her lean body mass and/or her levels of serum haemoglobin, then treating like cases
alike means requiring her to reduce her testosterone levels to below 5 nmol/L in order to compete
in the female classification in the most obviously affected events.
To the best of our knowledge, there is no other genetic or biological trait encountered in female
athletics that confers such a huge performance advantage. And certainly the sport has neverconsidered that competing against an athlete with any other type of genetic or biological advantage
was not fair and meaningful. For example, it does not see the need for weight categories or heightcategories (or any other categories, other than age) in order to preserve fair and meaningfulcompetition. Instead, it regards such factors as part of the combination of natural talent andsacrifice and determination that the sport seeks to celebrate. If that were to change in the future,e.g., if height were deemed to confer an unfair advantage in a particular event, then it might become
appropriate to introduce height classifications. Until then, however, it is appropriate to treat such‘natural’ advantages differently from the advantage that a female athlete with a DSD gets from herelevated levels of circulating testosterone.
What is the IAAF’s position in relation to trans athletes?
The IAAF also has an inclusive approach to the participation of trans athletes in sport, currently
reflected in its Regulations Governing Eligibility of Athletes Who Have Undergone Sex Reassignment
to Compete in Women's Competitions (see https://www.iaaf.org/about‐iaaf/documents/medical). It
is currently reviewing and updating those regulations in light of the evidence identified above and inlight of the learnings from the IOC’s 2015 Consensus Meeting on Sex Reassignment andHyperandrogenism(https:/stillmed.olympic.org/Documents/Commissions_PDFfiles/Medical_commission/2015‐
11_ioc_consensus_meeting_on_sex_reassignment_and_hyperandrogenism‐en.pdf), and expects toissue updated regulations on this topic in the coming months.

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ELIGIBILITY REGULATIONS FOR THE FEMALE CLASSIFICATION(ATHLETES WITH DIFFERENCES OF SEX DEVELOPMENT)EXPLANATORY NOTES/Q&A
Who is the contact at the IAAF for further information?
Athletes, athlete support personnel and National Federation officials with questions about theapplication of the new Regulations may contact the IAAF Medical Manager, as follows:
IAAF Medical Manager
Health and Science Department
International Association of Athletics Federations
6‐8, Quai Antoine 1er, BP 359, MC 98007 Monaco Cedex
Email: medical.confidential@iaaf.org
Press queries should be directed to:
IAAF Communications Department
International Association of Athletics Federations
6‐8, Quai Antoine 1er, BP 359, MC 98007 Monaco Cedex
Email: newsinfo@iaaf.org

Issued by the IAAF Health & Science Department
1 May 20198