The essence of sport is a competition, played under rules, with an unpredictable outcome. 

By Louis Weston, Barrister, Outer Temple Chambers

1. The fundamental importance of an unpredictable outcome requires in some sports, sometimes, that there is a levelling of the resources of the competitors: in horseracing horses can be required to carry weights to compensate for better ratings and/or lighter jockeys, in judo, judokas compete at different weight classes.

2. Weight is not the only leveller of the competition in Kendo, the competitors compete according to their assessed skill classifications and in parasport athletes are graded by the extent of the activity limitation resulting from their impairment, and where runners use prosthetics they are prevented from using prosthetic blades that are unduly long by application of the Maximum Allowable Standing Height rules which measures athletes against an assessed and recorded height.

3. Often but neither universally or necessarily, by example horseracing, eventing and NASCAR, sport also levels competition by gender classification. Those sports that are ‘gender neutral’ may sometimes have gender classified competitions and for some events not.  So that, in shooting there are gender classifications for the Olympics but not in some national competitions.  Lest the presumption be that these classifications are to advantage female athletes, shooting results have shown that female shooters are frequently higher scorers in some shooting disciplines[1].

4. There are some incongruities across sport where levelling does not take place. Basketball and volleyball do not place limits on the height of players, so one team may field a very tall player with some obvious physical advantage, and in rugby larger players run on the same field as smaller players.  Height may also be an advantage in some athletic sports, yet the 100m or the high jump do not have height limited classifications to enable equality of competition for shorter athletes.

5. All that of course is based on adult sport, somewhat oddly, domestically, sport for children is generally based upon age classification. That classification is informative as between the ages of 12 and 18 often a school/club team will be able to field one child athlete who is significantly stronger, larger or more substantially built than the other children and in rugby that concern[2] has led at least New Zealand to operate a weight classification for children at provincial level[3] and a national under 85kg competition[4].

6. At the other end of the circle of life, many sports run seniors, veterans and minimum age classified sports age spectrum, so World Masters Athletics[5] organises that sport for persons over 35 and up to 105 with Stanislaw Kowalski holding the record for the men’s 105 year old 100m at 34.5 seconds (set in June 2015) and Julia Hawkins the women’s 105 year old 100m at 1 minute and 2 seconds (having previously held the 100 year old records at 39.62 seconds).

7. In that context of sport being able to adjust its rules and regulations to secure a level competition, how should domestic sport address the participation of Transgender Athletes under the Equality Act 2010?

8. In discussing that question I adopt the terminology used in For Women Scotland Ltd v The Scottish Ministers [2025] UKSC 16[6] that
   1. A person who was at birth a person of the male sex is described as a biological male, and a ‘trans woman’ if that person comes to have the protected characteristic of gender reassignment
   2. A person who was at birth a person of the female sex is described as a biological female, and a ‘trans man’ if that person comes to have the protected characteristic of gender reassignment

The issues apparently raised by Transgender Athletes Participation in Sport

9. Let me start with what, I think, are self-evident propositions:
   1. First, for many people in individual or social sport, whether sport is played against a biological man, or a biological woman, a trans man or a trans woman, is not an important legal question; who plays who and who participates is consensual. Where there is a need for consideration of regulation of how biological men and women should engage in sport it is probably in competitive or team sport.
   2. Second, for at least pre-pubescent children sport can be engaged in without gender classification. Children can without difficulty compete without gender classification as is recognised in Equality Act[7].  There is an argument about the age that may cease but not for this article.
   3. Third, athletic ability, skill, talent and endurance are not evenly distributed across populations. It is obvious that many biological women are faster, fitter, stronger and more capable than many biological men, and vice versa.  Whilst the strongest, fastest and highest jumping person may be a biological man, there are many biological men who are themselves relatively less athletic than even moderately fit biological women.
   4. Fourth, there is not a homogenous population of trans gender athletes in the same way that there is not a homogenous population of biological men or women. So it is a false assumption that trans women will be better athletes than biological women.

10. The challenge those propositions raise is that in some competitive sport some trans women may be more likely to be athletically capable than at least some biological women who compete in that sport. In those circumstances sport must address the balance of partially preventing a person from living their life in their chosen gender, where to do so without restriction adversely impacts the opportunities of persons who compete as a person of their biological sex and have a right and wish to do so. For simplicity of discussion only I assume that typically this will be a question of a biological woman’s competitive chances being limited by the participation of a trans woman.

What is the Law?

11. For Women Scotland Ltd sets out straightforwardly the legislature’s involvement in the regulation of discrimination in sport. In summary:
    1. The Equality Act 2010 by its section 195 addresses Sport by stating:

(1) A person does not contravene this Act, so far as relating to sex, only by doing anything in relation to the participation of another as a competitor in a gender-affected activity.

(2) A person does not contravene section 29, 33, 34 or 35, so far as relating to gender reassignment, only by doing anything in relation to the participation of a transsexual person as a competitor in a gender-affected activity if it is necessary to do so to secure in relation to the activity— (a) fair competition, or (b) the safety of competitors.

(3) A gender-affected activity is a sport, game or other activity of a competitive nature in circumstances in which the physical strength, stamina or physique of average persons of one sex would put them at a disadvantage compared to average persons of the other sex as competitors in events involving the activity.

(4) In considering whether a sport, game or other activity is gender-affected in relation to children, it is appropriate to take account of the age and stage of development of children who are likely to be competitors.

1. The decision that within the Equality Act sex means biological sex, renders simple the meaning of section 195 which (paragraph 234) is that The exemption it creates is a complete exemption in relation to the prohibition against sex discrimination in sport in relation to the participation of a competitor in a sport that is a gender-affected activity (section 195(1)) and a partial exemption for gender reassignment discrimination in relation to the participation of a transsexual person as a competitor in a gender-affected activity but only where the treatment is necessary for fairness or safety reasons.  In both cases the exemption cannot apply unless there is a gender-affected activity.  This is a gateway condition.

12. The Supreme Court went on, at paragraph 235, to hold that a trans woman with Gender Recognition Certificates should not be included in the concept of a ‘average persons of one sex’.

13. Then using boxing as a self-evidently gender affected activity, held that using biological sex as the meaning of sex in the Act, had the consequence (paragraph 236) that a women’s boxing competition organiser could refuse to admit all men, including trans women regardless of their GRC status. This would be covered by the sex discrimination exception in section 195(1). But if, in addition, the providers of the boxing competition were concerned that fair competition or safety necessitates the exclusion of trans men (biological females living in the male gender, irrespective of GRC status) who have taken testosterone to give them more masculine attributes, their exclusion would amount to gender reassignment discrimination, not sex discrimination, but would be permitted by section 195(2). It is here that the gender reassignment exception would be available to ensure that the exclusion is not unlawful, whether as direct or indirect gender reassignment discrimination.

14. The observation that a trans man competitor could take testosterone to enhance performance, is both a simplification of a complex question of anti-doping control and the complicated issue of Therapeutic Use Exemptions (TUE) for Transgender Athletes which is at least partially addressed in WADA’s TUE Physician Guidelines – Transgender Athletes Prohibited Substances: Testosterone, Spironolactone[8].

15. Following For Women Scotland therefore the issue for transgender women’s participation in sport is essentially a binary question of whether the sport is a gender affected activity (GAA).

How and when does a Sport become a GAA?

16. The immediate questions, which I take in turn, that fall from the statutory definition of a GAA are
    1. First, which sports are so affected?
    2. Second, how might that issue be established?

17. A starting point is that the definition of GAA under section 195(3) is disjunctive and not a balancing exercise. The issue is whether any one of the factors physical strength or stamina or physique of the average person of one sex gives an advantage in that sport. It matters not if factors balance out where one is advantageous, so for Rugby where physique is an advantageous attribute the sport is GAA even where the sport itself has wild disparate physiques in the same teams and props typically leave the field after 60 minutes.

18. The test for a GAA has been addressed after First Women for Scotland in Haynes v Thomson [2025] EWCC 50, which whilst an obiter decision of a Circuit Judge in the County Court is informative:
    1. In that case the Defendant was the English Blackball Pool Federation, an unincorporated association that established the rules for that form of the sport of pool. In 2023 the Federation changed its rules to allow only biological females to play in female competitions and teams, that rule change had the effect of preventing Ms Haynes, a trans woman, from competing in female competitions under the governance of the Federation which she claimed to be direct discrimination on the grounds of gender reassignment.
    2. Ms Haynes’ claim failed because following For Women Scotland the discrimination in Ms Haynes’ case was not gender re-assignment discrimination (her pleaded case paragraph 85), but permitted sex discrimination because she was a biological man.
    3. The Court nonetheless went on to consider whether the sport of pool was a GAA (paragraphs 125 et seq) in these stages:
       1. First, asking what in section 195(3) is an ‘average person’, deciding that the question involves two sub-questions:
       2. a) which population should be used for the average person, competitors in the sport or the population at large? The Court found for the former.
       3. b) whether in the circumstances of the sport in question that created a more than minimal disadvantage[9]?
       4. Second, considering whether there was evidence of such disadvantage. Evidence considered was in two forms, a rating system for players which showed men to be rated higher than women in a slightly different form of pool, and second expert evidence from a physicist/engineer and experts in sports medicine/biology.

• Third, finding that the sport of pool depends heavily on the break off a shot which requires controlled power achieved with high cue speed (paragraph 239) and that the average biological male being stronger can achieve higher cue speed (paragraph 242) and also a biological male having a larger frame can bridge without a rest more easily (paragraph 246) were both advantages average biological males enjoyed.

1. Fourth, dismissing hormonal differences as not likely to impact on the criteria of section 195(3) (paragraph 249).
2. Fifth, finding that if this were a case of gender reassignment discrimination (which it was not) that a prohibition on biological males/ trans women competing against biological females could not be avoided (by way of a handicap system for example) so as to render the prohibition unnecessary to secure fair competition or the safety of the competitors (cf section 195(2)).

19. If the broad approach taken in Haynes v Thomson is correct then a sport which does confer a benefit on a competitor who is a biological male and therefore on average physically stronger or on average larger, will be a GAA. That plainly is a wide range of sports and will lead to legally justified exclusion of trans women from competition against biological females.
20. It is to be anticipated that where there is a need to prove a sport is GAA, expert evidence from a coach/participant will be needed but if the Courts follow the broad test in Haynes the costs risk of running an expert case will be high in most sports. It would seem unarguable that on the Haynes approach biological men are at an average stronger and bigger that biological women, and that in those circumstances where size or strength are of import to the contest the test will be met.

Issues that arise

21. Haynes is not binding, and its approach is open to challenge and consideration.

22. The metric of average persons of a particular biological sex who compete in sport, and using the disadvantage the differential creates in relatively elite performance aspects in sport may not be the correct interpretation of the criteria for GAA and may not be the right question at all levels of sport. A question is: Whether at club level rather than at elite level, trans women should be excluded from club competitions open to females where the average player (of either biological sex) does not possess the skill to render manifest the advantages that their biological sex conveys? – in the language of section 195(3) does events in considering GAA mean all events in that sport at any level, any events at any level, or events at the level of the specific competitor? The language of section 195(4) – which enjoins assessment of age/development of children – would lend to a consideration at every level not at all sport for all levels.

23. If population averages for biological sex are applied, then itis obvious that biological males have greater physical strength or more substantial physique and begs the question of why the statute does not simply ask the question whether being stronger or larger is an advantage. Perhaps a question of poor drafting or again a question of assessing in the context of the event in the sport rather than averages at population level.

24. It is difficult to envisage (and this follows in part from the discussion in For Women Scotland in the context of gender recognition certificates) when a trans woman would suffer gender reassignment discrimination in sport, if the exclusion of trans women was always permitted sex discrimination and never gender reassignment discrimination – what the purpose does section 195(2) serve for trans women? It is arguably an open question (after For Women Scotland ) that section 195 (1) permits sex categorisation in a sport which is a GAA but in a sport which is not a GAA section 195(2), focussed on the individual athlete, requires in relation to gender reassignment discrimination not only that the GAA gateway is crossed, but also that in relation to the specific activity for that person to allow that trans woman to compete would be unfair to competition or unsafe. A slightly built trans woman would not thereby be prohibited from some sports; whilst a strongly built transwoman might be.

25. Further, the question for each sport will be to show that it has some evidence base for the decision that its sport is a GAA and the specific activities within that sport are affected by the biological sex of the competitors and potentially by the characteristics of the specific athlete.

26. Whilst therefore most Sports Governing Bodies can take strong support from the decision in For Women Scotland that gender classification of competition is lawful, it is unlikely that it is the end to the challenges that will be brought.

27. Finally, nothing prevents a Sport from encouraging the participation of all athletes and persons of any biological sex or experienced sex. It is apparent from the very many other means of protecting the safety of participants in sport the competitiveness of sport set out at the outset of this article that sport can accommodate different skills, sizes and strengths of athletes by application of considered criteria.

 Louis Weston Barrister, Outer Temple Chambers

[1] https://www.theguardian.com/sport/article/2024/jul/28/women-often-outperform-men-in-olympic-shooting-is-it-time-for-open-events

[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC8223073/pdf/fphys-12-670720.pdf See the discussion in the Paper A Comparison of An Alternative Weight-Grading Model Against Chronological Age Group Model for the Grouping of Schoolboy Male Rugby Players

[3] https://d26phqdbpt0w91.cloudfront.net/NonVideo/d4dc53a9-e9e5-43d4-8ac9-ba661346e66f.pdf

[4] https://www.nzrugby.co.nz/teams-and-competitions/national/under-85kg-club-cup/under-85kg-club-cup-faqs

[5] https://world-masters-athletics.org

[6] Para. 6

[7] Cf section 194(4) of The Equality Act 2010.

[8] https://www.wada-ama.org/sites/default/files/2022-01/TUE%20Physician%20Guidelines_Transgender%20Athletes_Final%20%28January%202022%29.pdf

[9] The Court took a very wide meaning of disadvantage as being relevant including (paragraph 137) prospective disadvantage after some training.