I. ABOUT SCIENCE AND SEX
A1. We mean no disrespect by using “males who identify as transgender” to include transwomen, gender-fluid, and nonbinary athletes. Our goal is to clarify: Unlike gender identity, sex is immutable. Males cannot transform into females, regardless of gender identity and regardless of whether they choose to embrace or reject gender stereotypes.
Most males (about 70 percent) who call themselves women have not had any medical treatments. (Washington Post/Kaiser Family Foundation poll, 2023.) Only about 16 percent have had surgery. Therefore, in the majority of cases, when a man “transitions” to a woman, only a “social transition” (hair, makeup, behavior) occurs.
Biological sex is the designation of an individual as male or female based on reproductive organs and associated primary and secondary sex characteristics. People are either female with ovaries/eggs and an estrogenic endocrine system, or are male with testes/sperm and an androgenic endocrine system. Accordingly, we use female, girl (young female), woman (adult female) and male, boy (young male), and man (adult male) to indicate biological sex.
A2. Sex differences are anatomical and physiological differences that are determined by or related to biological sex. Males on the one hand and females on the other have distinct genetic and chromosomal, gonadal, endocrinological, and phenotypic (external secondary) characteristics. The field of sex differences in biomedical research specifically studies these distinctions, which have implications not only for reproduction and sport, but also for immunology and cardiovascular health, among other things. As the Institute of Medicine has explained, “basic biochemical differences” exist between males and females even “at the cellular and molecular levels.”
A3. We have separate-sex sport and eligibility criteria based on biological sex because this is the only way we can assure that female athletes have the same opportunities as male athletes not only to participate but also to win in competitive sport. We also separate males and females in contact sports for reasons related to on-the-field playing-safety.
From the onset of male puberty, male bodies develop such that they are as a group faster, stronger, and more powerful than female bodies as a group. The performance gap between male and female athletes that emerges from that point typically ranges from 8-20%, but up to 50% depending on the sport and event.
Even pre-puberty, males have substantial testosterone-based advantages, which begin before birth. In utero, male fetuses receive an infusion of testosterone that is later associated with young boys’ somewhat greater strength1 and somewhat greater propensity for aggression – the androgenic effects of testosterone.2 For example, fitness data from over 85,000 children in Australia showed that, compared to nine-year-old females, nine-year-old males were 9.8 percent faster in sprints (running) and 16.6 percent faster in the mile run. They could jump 9.5 percent farther, could complete 33.3 percent more pushups in 30 seconds, and had a 13.8 percent stronger grip.3
Significant male advantage was also found in a study of Greek children pre-puberty. Compared with six-year-old females, six-year-old males completed 16.6 percent more shuttle runs in a given time and could jump almost ten percent farther from a standing position.4 Another Danish study showed six- and seven-year-old males had a higher aerobic capacity (VO2max) than girls in the same age group.5
A 2022 analysis of American swimming records showed that boys’ records in the ten- and-unders (nine and ten-year-olds) average 0.57 seconds faster per 100 yards than girls’ records. Boys’ records jump to an average of 3.01 seconds faster per 100 yards for the 12-and-under group and more than 4.5 seconds faster per 100 yards between the ages of 13 and 18. Jerry Giordano, an attorney who conducted the analysis, concluded that “about two-thirds of the eventual male-female differential in the performance of top swimmers emerges by the age of 12.”6 The pattern is even more dramatic in children competing in track. Every USA Track & Field age-group national championship record is better than the girls’ record. This is true beginning with the youngest competitive age group (eight-and-under), with the gap growing dramatically during and after puberty.
If we did not separate males and female athletes on the basis of biological sex – if we used any other physical criteria – we would never see females in finals and on podiums.
1 “Boys demonstrate, on the average, greater strength than girls at all ages. Sex differences throughout childhood are consistent, although small.” – Human Growth, Frank Falkner et al., 1978, Page 286.
2 Hooven, Carole, T: The Story of Testosterone, the Hormone That Dominates and Divides Us. New York: Henry Holt, 2021.
3 Mark J Catley and Grant R Tomkinson, “Normative health-related fitness values for children: analysis of 85,347 test results on 9–17-year-old Australians since 1985,” British Journal of Sports Medicine, Vol. 47, Issue 2 (January 2013)
4 Tambalis KD, Panagiotakos DB, Psarra G, et al. Physical fitness normative values for 6–18-year-old Greek boys and girls, using the empirical distribution and the lambda, mu, and sigma statistical method. Eur J Sport Sci. 2016;16(6):736–46, cited in Hilton EN, Lundberg TR. Transgender Women in The Female Category of Sport: Perspectives on testosterone suppression and performance advantage. Sports Medicine. 2021;51: (PMID 33289906 and doi: 10.1007/s40279-020-01389-3).
5 Eiberg S, Hasselstrom H, Grønfeldt V, et al. Maximum oxygen uptake and objectively measured physical activity in Danish children 6–7 years of age: the Copenhagen school child intervention study. Br J Sports Med. 2005;39(10):725–30, cited in Hilton EN, Lundberg TR. Transgender Women in The Female Category of Sport: Perspectives on testosterone suppression and performance advantage. Sports Medicine. 2021;51: (PMID 33289906 and doi: 10.1007/s40279-020-01389-3).
6 Jerry Giordano, “The Boy-Girl Difference in Swimming Records,” Ricochet, June 25, 2022.
A4. No. There are no other physical criteria that could be used to determine eligibility that would similarly assure sex equality in competitive sport. Based on those different criteria, e.g., matching leg length, wing span, height, weight, etc., males as a group would always outperform females as a group because their biological sex differences–primarily testosterone levels in the male range from the onset of puberty and throughout the athletic career. Team USA stars Missy Franklin and Ryan Lochte illustrate this point well. They are both multiple Olympic and world champions in swimming. Both had first class training, coaching, and support. Both are 6’2” with reported 6’4” wingspans. Both held the world record in the 200 meters backstroke. But had they raced each other on their best days, Lochte would have finished about a half lap ahead of Franklin. In 2012, the year Franklin set her world record, her time of 2:04.06 would have placed her in a tie for 50th in the U.S. men’s Olympic Trials.
A5. No. Testosterone-driven sex differentiation at puberty results in males developing larger hearts and higher capacity for oxygen transport and carbohydrate processing, as well as different skeletal and muscular composition. All of these characteristics provide males with superior strength, speed, power, and endurance.
A6. Experts estimate the male advantage is normally between 8 and 20% depending on the sport and event, and up to 50% in sports and events featuring explosive power. For example: Team USA’s best female high jumper is Vashti Cunningham, NFL star Randall Cunningham’s daughter. She is regularly ranked among the top ten best female high jumpers in the world. Her best jump as a professional (6’ 7 ½”) is regularly surpassed by dozens of U.S. high school boys.
As the chart immediately below – comparing California high school performances – shows, this isn’t a phenomenon exclusive to professionals. Because the performance gap emerges at the onset of male puberty, as a group, high school girls have no chance against high school boys as a group.
2019 CALIFORNIA REGIONAL HIGH JUMP RESULTS
 This chart is based on data from Athletics.net, California High Jump Results, accessed on September 25, 2019.
A7. No. It is a fact – not myth or outdated stereotype – that starting from the onset of male puberty, i.e., starting in middle school, there is an average 8-20% performance gap between males and females, which reaches to 50% in some sports and events. The proposition that better resources and support for female athletes can change biological imperatives and competitive results is false. Some individual females can and will outperform some individual males. But even the very best female athletes are routinely surpassed not only by the very best male athletes but also by second tier male athletes. For example, the world records in the men’s and women’s shot put are close – 77’31/2” for the men and 74’23/4” for the women. But the women’s shot put is 8.8 lbs. while the men’s is almost twice as heavy at 16 lbs. The same pattern holds for the women’s world records in all of the races on the track from 100 meters to 10,000 meters. Indeed, not only are those records surpassed by many men each year, they are also surpassed by many high school boys. The pattern also holds for high school athletes who aren’t yet superstars. With rare exceptions, from the onset of male puberty, even the best high school girls have no chance to succeed against high school boys. Further, the pattern is true pre-puberty. Every USA Track & Field age-group national championship record is better than the girls’ record. This is true beginning with the youngest competitive age group (eight-and-under), with the gap growing dramatically during and after puberty.
A8. Testosterone is an anabolic-androgenic steroid. Anabolic steroids build body tissue, including but not limited to bone and muscle tissue and red blood cells. Androgenic steroids are responsible for male sex differentiation, i.e., for the development of male primary sex characteristics (in utero), and male secondary sex characteristics (in puberty). Because of its body building and sex differentiation effects, testosterone produced endogenously (naturally within the human body) is the primary driver of the sex differences in athletic performance, i.e., of the performance gap between male and female athletes. Beginning at puberty, at approximately age 11, the male testes begin producing significantly more testosterone than they did earlier in childhood, and also significantly more than is ever produced by female ovaries. This increased production triggers the onset of male puberty, and thereafter builds and sustains the male body in the respects that matter for sports performance: speed, strength, power, and endurance.
Pre-puberty, males also have substantial testosterone-based advantages, which begin before birth. In utero, male fetuses receive an infusion of testosterone that is later associated with young boys’ somewhat greater strength and somewhat greater propensity for aggression – the androgenic effects of testosterone. See question 3 for more detail.
The exogenous use of testosterone (doping) is banned by all national and international sports organizations because of these anabolic effects.
A9. Both males and females produce testosterone naturally in their bodies, males primarily in the testes and females primarily in the ovaries. Starting from the onset of male puberty, generally about age 11, testes begin to produce much more testosterone than ovaries. From that point forward, the normal female range is between 0.06 and 1.68 nanomoles per liter (nmol/L), and the normal male range is between 7.7 and 29.4 nmol/L. The gap between top of the female range and the bottom of the male range is 6.02 nmol/L. Converted to ng/dL – the metric typically used in medicine in the U.S. – the normal female range is from 1.73 to 48.45 ng/dL, the normal male range is from 222 to 848 ng/dL, and the gap between the top of the female range and the bottom of the male range is 173 ng/dL. The figure below was published in 2020 in the Journal of the American Medical Association (JAMA). It represents data from the U.S. National Health and Nutrition Examination Survey (NHANES). It shows the increase in testosterone concentration in male youth starting from age 11 onward, as well as the gap that emerges as a result between male and female testosterone levels.
A10. No. Although females do produce testosterone, mainly in their ovaries, healthy post-pubertal females never produce testosterone levels as high as post-pubertal males. Throughout childhood, up until the onset of male puberty, male and female testosterone levels are about the same; but from the onset of male puberty, male testes produce significantly more testosterone than female ovaries. From that point forward, normal female testosterone levels fall in a narrow range between 0.06 and 1.68 nanomoles per liter (nmol/L), and male levels fall in a broader range between 7.7 and 29.4 nmol/L. The gap between the normal male range and the normal female range is wide. As the following figure indicates, there is no overlap. Some biological females have higher than normal female testosterone levels, for example if they have polycystic ovaries, but again, no healthy female has a testosterone level even close to the normal male range.
This figure shows the normal female testosterone range on the left and the normal male range on the right. Abnormal testosterone ranges can be produced by people with certain differences of sex development (DSDs). Some people with DSD prefer to describe themselves as intersex. The conditions that affect genetic (biological) females are all below the male range. The conditions that affect (genetic) biological males are all above the female range. Those conditions are described further in the answer to Question 27 below.
Some advocates for trans and intersex athletes claim that there is an overlap in the normal ranges. This claim is not supported by the data or the current peer-reviewed literature. Their argument depends on the existence of a small number of outlier (abnormal) readings, i.e., on a small number of higher-than-normal female T readings and a small number of lower-than-normal male T readings. These abnormal readings are used by advocates to construct a “spectrum” that appears to negate the normal bimodal distribution by “filling in” the gap between the two ranges. It requires ignoring that more than 99% of the population has readings in the normal ranges, and then “filling in” the gap between those ranges with readings from the less than 1% of the population that has an intersex condition.
As the leading experts in the field have established, however, the overlap argument is not supported by the data points themselves, which do not distinguish between (1) doped and non-doped females; (2) females and males with differences of sex development; and (3) male readings taken at rest and following strenuous exercise—the latter has been established to lower normal levels temporarily. Additionally, they measure testosterone by immunoassay – which is inaccurate at lower testosterone concentrations in women – rather than by state-of-the-art methodology, i.e., by mass spectrometry. Once those errors are corrected, the overlap disappears.
 Advocates may refer to this older paper to support their claim: Healy ML, et al., Endocrine profiles in 693 elite athletes in the postcompetition setting. Clin Endocr. 2014; 81(2): 294-305. PMID: 24593684.
 Handelsman DJ, Hirschberg AL, Bermon S. Circulating Testosterone as the Hormonal Basis of Sex Differences in Athletic Performance. Endocr Rev. 2018;39(5):803-29. Epub 2018/07/17. Clark RV, Wald JA, Swerdloff RS, Wang C, Wu FCW, Bowers LD, Matsumoto AM 2019 Large divergence in testosterone concentrations between men and women: Frame of reference for elite athletes in sex-specific competition in sports, a narrative review. Clin Endocrinol (Oxf) 90:15-22.
A11. No. Elite female athletes generally have testosterone levels within the normal female range, i.e., below 1.68 nmol/L. If they have the condition known as polycystic ovary syndrome (PCOS), they may have testosterone levels up to 3 nmol/L, or, in rare instances, up to 4.8 nmol/L. This is why some sports organizations, wishing to be inclusive of all possible healthy biological females, set their maximum testosterone level at 5 nmol/L.
A12. Testosterone is an excellent proxy for biological sex and a valid basis for an eligibility rule for the women’s category for the following reasons:
- Testosterone is the primary driver of the sex differences in athletic performance;
- Sport already tests for and monitors testosterone levels as part of the normal anti-doping process; and
- Different sex testing protocols are more intrusive and, in some cases, less accurate.
No other single criterion so comprehensively addresses sport’s and society’s concerns about the testing protocol.
A13. Some sports organizations have adopted the level of 5 nmol/L as the upper limit for inclusion in the female category because it represents the outermost bounds that a healthy biological female – regardless of her legal or gender identity – can reach naturally. Almost all females, including elite athletes, have testosterone levels well below 5 nmol/L. The normal female range is between 0.06 and 1.68 nmol/L. Even females with the condition known as polycystic ovary syndrome (PCOS) – which can dramatically raise testosterone levels – only very occasionally reach 3 nmol/L, with rare readings up to 4.8 nmol/L. Setting the level at 5 nmol/L assures that no otherwise healthy biological female could be excluded by the standard. Given that 5 nmol/L is already high, however, some international federations are considering the lower limit of 3 nmol/L.
A14. The female category was carved out from open (mixed or co-ed) sport as a protected space where females could compete only against each other and not also against males. It was designed specifically to exclude males, i.e., people with male sex-linked performance advantages. Testosterone is the primary driver of these sex-linked advantages. The male category is not policed because it does not need protection from itself; it was not designed to exclude or regulate males with natural male testosterone levels. Elite sport does, however, monitor testosterone levels in all athletes, male and female, for exogenous use of (i.e., doping with) androgens, including testosterone.
A15. No. They are wrong. Males who identify as transgender are biologically male. There is overwhelming evidence that individuals who are biologically male – however they identify – have an athletic advantage over individuals who are biologically female—however they identify. Gender identity has nothing to do with athletic ability. Additionally, there is convincing evidence that, depending on the task, skill, sport, or event, males who identify as transgender maintain male sex-linked (legacy) advantages even after multiple years on standard gender-affirming hormone treatment.
 (1) Roberts TA, Smalley J, Ahrendt D. Effect of gender affirming hormones on athletic performance in transwomen and transmen: implications for sporting organisations and legislators. Br J Sports Med. 2020. Epub 2020/12/09. (2) Hilton EN, Lundberg TR. Transgender Women in The Female Category of Sport: Perspectives on testosterone suppression and performance advantage. Sports Medicine. 2021;51:(in press) (PMID 33289906 and doi: 10.1007/s40279-020-01389-3). (3) Handelsman DJ, Hirschberg AL, Bermon S. Circulating Testosterone as the Hormonal Basis of Sex Differences in Athletic Performance. Endocr Rev. 2018;39(5):803-29. Epub 2018/07/17. See also (4) Gooren LJ, Bunck MC. Transsexuals and competitive sports. Eur J Endocrinol. 2004;151(4):425-9. (5) Wiik A, Lundberg TR, Rullman E, et al. Muscle Strength, Size, and Composition Following 12 Months of Gender-affirming Treatment in Transgender Individuals. J Clin Endocrinol Metab. 2020;105(3). Epub 2019/12/04.
A16. No. They are wrong. Although stereotypes and opportunities can affect the degree of the performance gap between the best females and the best males, the data and science are clear that for almost all sports and events we know that the gap itself is biologically-based and immutable.
A17. A transgender person is currently defined as someone whose identifies as other than their biological sex. For example, a male who identifies as transgender is someone who identifies as a girl/woman even though they are biologically male. A person does not need to take gender-affirming hormones or have surgery to be considered transgender. Some transgender people are not on hormones and have not had surgery. Some transgender people take hormones but do not have surgery. And some transgender people do both. Whether a transgender person takes hormones, the level at which they choose to set their hormones, and whether they have surgery, are all matters of personal choice, medical advice, and/or opportunity.
Transgender does not mean what transsexual used to mean. According to recent research by the Washington Post and the Kaiser Family Foundation, 62 percent of trans adults identify as “trans, gender non-conforming” or “trans, nonbinary,” while only 33 percent identify as a “trans man” or “trans woman.” Just 31 percent have used hormone treatments, HRT, or puberty-blocking hormones, and only 16 percent have undergone “gender-affirming” surgery or another surgical treatment to change their physical appearance.4 This survey was conducted on adults; one can reasonably assume that schoolchildren and college students are even less likely to have used medication or undergone surgery. Therefore, the vast majority of males who identify as transgender (at least 84 percent) who seek to compete against female athletes have not had surgery, and at least 69 percent have not taken any medications.
A18. Yes – Even those males who identify as transgender who never experience the onset of male puberty because they take puberty blockers before its onset, retain their pre-puberty testosterone advantage. The degree of their legacy advantage depends on a combination of factors including: the extent to which they have experienced puberty; whether they had a gonadectomy (surgical removal of their testes); the levels at which they maintain their circulating testosterone; and the particular sport and event in which they compete. Most importantly, even pre-puberty, males have substantial testosterone-based advantages, which begin before birth. Avoiding male puberty does not turn boys into girls. See Question 3 for a more extensive discussion.
A19. Legacy advantages are the male sex-linked advantages that remain even after a male who identifies as transgender has gone on gender-affirming hormones and/or gender-affirming surgery. They are the benefits of having gone through all or part of puberty as a male. Males who identify as transgender maintain physiological, sex-linked (legacy) advantages even after multiple years on gender-affirming hormone treatment such as testosterone-suppression drugs. For example, hormone treatments do not affect height.1
1 Hilton EN, Lundberg TR. Transgender Women in The Female Category of Sport: Perspectives on testosterone suppression and performance advantage. Sports Medicine. 2021;51: (PMID 33289906 and doi: 10.1007/s40279-020-01389-3).
A20. Doping is the exogenous use – the taking – of prohibited performance enhancing drugs (PEDs), including testosterone and other body building androgens. These are among the substances that propelled the East German women to victory in the Olympic Games and World Championships in the 1970s and 1980s, costing clean American women and Team USA (and others) to lose out on medals they would otherwise have won. Some American athletes have also doped with androgens, but not in the systematic and state-sponsored way as the East Germans, and more recently the Russians. Males who identify as transgender who want to be included in girls’/women’s competitive sports events are not doping; that is, they aren’t taking PEDs to compete. But their natural testosterone levels build strength, speed, and power in the same way that doping does; and because their natural levels are much higher than even those of doped female athletes, the effect on competition is the same or more overwhelming for the clean (common term for non-doping) females in the field.
A21. Yes. The data that exists about males who identify as transgender with no medical intervention is consistent with the fact that they are biologically male. For example, based on its interpretation of the State of Connecticut’s Equality Act, the Connecticut Interscholastic Athletics Conference (CIAC) permits transgirls to compete in girls’ events even if they have not yet gone on puberty blockers or gender-affirming hormones. (The CIAC places no physical or physiological conditions on their inclusion in girls’ sports.) Two males who identify as transgender who used to compete on their schools’ boys’ track teams moved to the girls’ teams when they came out as transgender. They immediately dominated their events at their conference, state, and regional competitions, even though their performances would have been insufficient to qualify them for post-season competition had they competed in the boys’ divisions. And although they started competing in girls’ events before they began taking gender-affirming hormones, they continued to be among the best in the girls’ events even after they publicly stated they had started on puberty blockers and hormones. All told, just these two males who identify as transgender took “15 girls’ state championship titles (titles held in 2016 by nine different Connecticut female athletes) and . . . more than 85 opportunities to participate in higher level competitions from female track athletes in the 2017, 2018, and 2019 seasons.”
T MILLER – SPRINTS – 55 meters indoors and 100 meters outdoors
Miller, one of the males who identify as transgender, competed on the boys’ track team her freshman year and through the winter of her sophomore year. She came out publicly as transgender in the middle of 10th grade, and then switched to the girls’ team for her remaining two-and-a-half years of eligibility.
Her hormone status for each season is derived from publicly available information. Because that information indicates she went on hormones for the first time only at the end of the 2019 outdoor season, i.e., sometime in May, and because her best time that year was run before then, she is listed here as “not on hormones” for the year.
The table shows rankings for the 55 meters indoors first, followed by the 100 meters outdoors. The rankings in blue font show the division she actually competed in, and the point at which she switched from the boys’ to the girls’ division. Simply by walking off of the track in the boys’ events and walking onto the track in the girls’ events, she went from barely being in the top 400 in the state boys’ interscholastic competitions to being #1 in the state among girls’ interscholastic competitions.
The girls’ competition rankings for her 9th grade year are those she would have achieved based on her times as run in boys’ events. The boys’ rankings for her sophomore, junior, and senior years are those she would have achieved based on her times as run in girls’ events. There were no rankings for the 100 meters outdoors her 12th grade year (2020) because the season was cancelled due to COVID.
A YEARWOOD – SPRINTS – 55 meters indoors and 100 meters outdoors
Yearwood, the other male who identifies as transgender, competed on the girls’ team all four years in high school. She came out publicly as transgender in the 9th grade. Her hormone status for each season is derived from publicly available information. The table shows rankings for the 55 meters indoors first, followed by the 100 meters outdoors. The boys’ competitions rankings listed on the table are those she would have achieved based on her times run in girls’ events. There were no rankings for the 100 meters outdoors her 12th grade year (2020), because the season was cancelled due to COVID.
We don’t have statistics on the number of males who identify as transgender who have competed in girls’ events in high school sports. However, it appears that, at least in the past, most were already on gender-affirming hormones by the time they sought to participate on girls’ teams; transgender advocacy groups seems generally to assume that this is the case when they speak to the issue. However, we are at a juncture in history where males who identify as transgender who are not on hormones are just beginning to ask to be included in girls’ competitions and state laws mandate their inclusion. In part this is because the standard of care in transgender medicine now recommends that transkids “come out” socially before they transition medically; and many physicians now require that kids wait until they are 16 to go on gender-affirming hormones. For a male who identifies as transgender, going out for a girls’ school sports team is one way to come out socially. We are thus increasingly likely to face situations like that in Connecticut where males who identify as transgender seek to compete in girls’/women’s sport while not on hormones.
 Verified Complaint for Declaratory and Injunctive Relief and Damages, Seoule et al. v. CIAC, Case No. 3:20-cv-00201, paragraph #77, filed in the United States District Court for the District of Connecticut (Feb. 12, 2020). These results are limited to conference, state and regional championships. They do not include all of the regular season or invitational events at which opportunities to move on through competitions to finals and/or wins and podium spots were affected.
 See, e.g., Beyond the Labels: Meet Terry Miller, Runner’s Space.com, May 26, 2019, available at https://www.runnerspace.com/gprofile.php?mgroup_id=44531&do=news&news_id=576791 (implying that Miller attended NSAF Nationals as a spectator not a competitor in her junior year, 2019, because she was not eligible to compete there due to the NSAF’s eligibility policy, which mirrored that of USATF, the NGB, not the CIAC, and Miller herself suggesting that she began taking hormones only in the latter part of that same year).
 See, e.g., Jeff Jacobs, As We Rightfully Applaud Yearwood, We Must Acknowledge Many Questions Remain, Hartford Current, June 17, 2017, available at https://www.courant.com/sports/hc-jacobs-column-yearwood-transgender-0531-20170530-column.html (reporting that Yearwood’s father “said his daughter will begin consultations in June  about hormonal treatment”). That was at the end of 9th grade. The fact that she competed at NSAF Nationals in 11th grade (March 2019) means that she was on hormones in 10th grade since their eligibility policy requires that transgender athletes be on gender-affirming hormones with their level below 5 nmol/L for 12 months before being eligible to compete in their events and then throughout their competitive seasons.
A22. Yes. The medical community now recommends that transkids “come out” socially before they transition medically. While some males who identify as transgender have opted to go out for a girls’ school sports team as one way to come out socially, this option is not so easily available to females who identify as transgender who, because of biological differences, are unlikely to be able to make a boys’ team. As a result, some females who identify as transgender have chosen to come out socially while remaining on girls’ teams. This has allowed them to continue to participate and to remain competitive in high school sport. Some males who identify as transgender have chosen this same path, coming out socially while remaining on the boys’ team.
A23. Going on gender-affirming hormones causes a decline in circulating levels of testosterone which, if consistently maintained over time, has some effect on athletic performance. This effect seems to be primarily on endurance, not on strength and power. The effect on speed seems to be dependent on the extent to which the event is endurance – as opposed to strength – and power-based. Thus, the nature and extent of the decline in male performance advantage, also known as the “legacy advantage”, appears to depend on the sport and the event. It also depends on the extent to which the individual experienced male puberty before they began their physical transition, and on how high they choose to maintain their testosterone levels once they do go on gender-affirming hormones. Regardless, as we explain in our answer to Question 15, the current state of the peer reviewed literature is that legacy advantages remain significant.
A24. The NCAA, the International Olympic Committee (IOC), and many international sport federations (IFs) and national sport governing bodies (NGBs), initially adopted eligibility rules that required males who identify as transgender to reduce their testosterone levels for at least a year before they would become eligible to compete in girls’/women’s events. This accommodation was a policy compromise, based in the hypothesis that if a male who identifies as transgender reduced her testosterone levels into the female range and kept her levels consistently within that range for at least a year, her male-linked advantages would decline to the point that it would be fair to include her in girls’/women’s competition. The hypothesis itself was based on the fact that males who identify as transgender are biologically male and that testosterone was the primary driver of the performance gap between male and female athletes. Just how much gender-affirming hormones reduced her male sex-linked advantages and what “legacy advantages” remained was still the subject of ongoing scientific investigation at the time such eligibility rules were adopted. However, we now know more. Research over the last couple of years has demonstrated that one year of hormone therapy is insufficient and legacy advantage is greater than originally hypothesized. Further, the transgender community has changed its original position supporting mitigation of testosterone as a condition of eligibility for competitive sport to insisting that unmitigated males who identify as transgender be eligible to participate.
In 2021, the IOC withdrew from its transgender eligibility governance responsibility and placed that responsibility into “the remit of each sport and its governing body to determine how an athlete may be at a disproportionate advantage against their peers, taking into consider the nature of each sport,” issuing vague guidance, the IOC Framework on Fairness, Inclusion and Non-Discrimination on the Basis of Gender Identity and Sex Variations. The Framework failed to clearly state that the rights of that subset of males who identify as transgender who have male sex-linked advantages would not be prioritized over the rights of females who do not have such advantages or to require that IFs adopt evidence-based inclusion that does not defeat the female physiological category. Notwithstanding this deficient IOC guidance, IFs now have the real authority under the Olympic Charter to establish eligibility standards for their sports, a process that was not completed by the end of 2022 and is still ongoing. It is expected that they will develop standards for including transgender women in female sport that are based in the best available scientific evidence about how sex differences impact safety and performance and that under such rules, women who identify as transgender will be included in female sport in ways that are not female category defeating. It is expected that NGBs, the USOPC, and other sports governing organizations, like high school federations and the NCAA, will adopt these rules consistent with science.
A25. Yes. As our answer to Question 15 details, several peer-reviewed studies, including one based on data from the U.S. military, have confirmed that males who identify as transgender retain their male sex-linked advantages even after a year on gender-affirming hormones. This is especially the case for sports and events that are not endurance-based. Because of these retained advantages, USA Powerlifting, World Rugby, and World Athletics (track and field) have recently concluded that it isn’t possible to fairly and safely include males who identify as transgender in women’s competition. Other international sports federations have rejected the International Olympic Committee’s 2015 guidance suggesting that males who identify as transgender be included in women’s competition so long as they reduce their testosterone levels to the bottom of the male range (under 10 nmol/L). Many federations have reduced the required testosterone level to within the female range and/or precluded post-puberty transgender athletes from competing in the female category.
A26. No. In January of 2022, the NCAA withdrew its 2010 outdated transgender eligibility rule that lacked both rigor and detail. The old rule provided only that males who identify as transgender be on gender-affirming hormones for at least a year, did not specify that they needed to bring their testosterone levels into the female range; did not require them to keep their levels consistently within that range; and the NCAA did not monitor their compliance. The updated NCAA policy calls for transgender participation in each sport to be determined by the policy for the national governing body of that sport, subject to ongoing review and recommendation by the NCAA Committee on Competitive Safeguards and Medical Aspects of Sports. If there is no NGB policy for a sport, that sport’s international federation policy would be followed. If there is no international federation policy, previously established IOC policy criteria would be followed.
Portions of the new policy were effective starting with the 2022 winter NCAA championships but full implementation does not begin until the 2024-25 academic year. Transgender college athletes competing until then will need to document sport-specific testosterone levels beginning four weeks before their sport’s championship selections. Starting with the 2022-23 academic year, transgender student-athletes need documented levels at the beginning of their season and a second documentation six months after the first. They will also need documented testosterone levels four weeks before championship selections. Effectively, the NCAA phase in process tells biological females to wait three years for fair competition.
A27. Intersex conditions result from differences in biological sex development. They are also known as differences of sex development or DSDs. There are many different intersex conditions, but those that are relevant for sport all involve biological males – individuals with an XY karyotype, testes, and testosterone levels in the male range – whose sex development was atypical in some respect. For example, their external genitalia might not be fully formed or their androgen receptors may be less than typically sensitive. Athletes with such intersex conditions may be raised as male or female. People who are transgender do not generally consider themselves to be intersex. The two are related in sport to the extent that they may both involve biological males with full or partial male advantage who seek eligibility to compete in girls’/women’s sport competition.
The following table is illustrative. It is from an exhibit in the case brought by South African runner Caster Semenya against her international federation (the IAAF now World Athletics) at the Court of Arbitration for Sport (CAS) in Switzerland. Semenya is sometimes described as intersex. In 2019, CAS upheld the federation’s eligibility rules for the women’s category. Those rules require affected athletes to verifiably reduce their testosterone levels to within the normal female range for a 12-month period before they can compete in that category. Switzerland’s Supreme Court affirmed the CAS decision in 2020.
COMPARING BIOLOGICAL SEX TRAITS FOR PURPOSES OF GIRLS’ AND WOMEN’S SPORT (from IAAF Exhibit in Semenya and ASA v. IAAF)
Note: MTF = Male to Female
II. ABOUT CURRENT LAW ON SEX AND SPORTS
A28. Separate-sex sport is regulated by a combination of statutes, regulations, and case law. This includes the Ted Stevens Olympic and Amateur Sports Act, Title IX and its regulations, the Equity in Athletics Disclosure Act, and court decisions interpreting their terms.
A29. No. They are wrong. The point of the laws that create and regulate separate-sex sport is to ensure that females have the same opportunities as males not only to participate, but also to succeed. In addition to competing, this includes the fair ability to win and set records in regional, national, and international competitions. No male or female has an individual legal right to win or set records in their respective divisions, but as a class, females have the legal right to win and set records in girls’ and women’s sport, just as males that have that right in boys’ and men’s sport.
A30. The re-definition of “sex” to include “gender identity” in a law that prohibits discrimination “on the basis of sex” would mean that programs receiving federal funds and operating in interstate commerce could not lawfully distinguish a biological female from a males who identify as transgender. This would make it prima facie unlawful to do what is currently permitted, i.e., to have teams and events that are separated on the basis of biological sex. It would also make it prima facie unlawful to use testosterone — a sex-linked trait — as an eligibility criterion for inclusion in girls’ and women’s elite sport, e.g., as is currently required by the NCAA, the USOPC, the IOC, and the national and international sports federations. Both separate-sex sport itself and eligibility criteria based on biological sex and sex-linked traits like testosterone, are currently lawful exceptions to general prohibitions on sex discrimination. For this to remain the case, the Equality Act which passed the U.S. House of Representatives but not the Senate during the 117th Congress (2021-22) and has been reintroduced during the 118th Congress (2023-2024) would need to be amended to provide for an express exception for biological female competitive sport.
A31. We don’t know. Many of the EA’s advocates argue that the proposed EA Act won’t affect Title IX, without explaining why. Alternatively, others argue that, even if it does, Congress could restore separate-sex sport after the EA’s enactment, through additional legislation or regulations addressing sport. However, we believe that restoring separate-sex sport after the EA’s enactment is highly unlikely as a matter of standard legal analysis, legislative history, and politics.
The EA is designed to amend the Civil Rights Act of 1964. The definitions in that statute have been and will continue to be the basis for interpreting or defining the same words as used in all other civil rights legislation. That is, Congress cannot re-define “sex” in the principal statute and not have that definition apply directly or indirectly to the use of that term in other legislation. In fact, many of the EA proponents intend precisely this—make the change to the definition in the principal legislation, and this will automatically change the definition in related legislation.
Moreover, as a matter of standard legal analysis, absent a legislative carve-out for sport — i.e., an explicit acknowledgement of an exception — any newly enacted, categorical prohibition on discrimination between biological females and males who identify as transgender would be presumed to supersede any earlier legislation to the contrary, including Title IX.
The legislative history of the EA makes clear that its proponents intend for it to apply to sport with no conditions or exceptions and thus, to prohibit any distinctions between biological females and males who identify as transgender. At the House Judiciary Committee Hearings, both the witnesses and Democrats on the Committee insisted that males who identify as transgender be included in girls’ and women’s sport without any conditions because “transgirls are girls, transwomen are women, period.” And on the floor of the House, a bill was rejected by a vote of 181 to 228 that would have retained the longstanding exception in Title IX for separate-sex sport based on biology. (Specifically, Congressman Steube proposed legislation providing that, “Nothing in this Act or any amendment made by this Act may be construed to diminish any protection under Title IX of the Education Amendments of 1972.”) The Equality Act then passed the House after a floor vote confirming that a significant number of legislators intended for it to apply to school sports. It failed in the Senate and so died in that session. It was revived in the Senate (S.5) and the House (H.R. 5) in 2023 with supportive legislators taking the same position as their counterparts in the House had with the earlier version.
The natural experiment with state versions of the EA also make it clear that an explicit exception is necessary to maintain sex-segregated sports and spaces. In those contexts, trans advocates argue that under the state EAs, it is impermissible to separate or in any way differently to treat trans-identifying female within girls’ sport. They make these arguments even though state legislatures did not consider sports as they were enacting their EA legislation.
A32. In Bostock, the Supreme Court ruled that “sex” in Title VII means “biological sex.” Contrary to what many proponents of the proposed Equality Act (EA) argue, Bostock did not define (or re-define) “sex” to include “gender identity.” Rather, it held that Title VII’s general prohibition of discrimination “on the basis of sex” precludes discrimination that takes into account a transgender employee’s sex and gender identity. Firing a person because they are transgender — i.e., because their gender identity is nonconforming — requires taking their sex into account, and this is prohibited by Title VII. Because the case involved Title VII’s general non-discrimination provision, not an existing exception that allows taking sex into account, the Court wrote that it was leaving the lawfulness of exceptions — including in bathrooms, locker rooms, and sport — for another day. Bostock explicitly did not rule on the lawfulness of the current scheme under Title IX and the other sport statutes.
Proponents of the EA nevertheless assert that Bostock applies to sport, completely ignoring the Court’s express pronouncement to the contrary. Specifically, in cases pending in the lower courts, they argue that Bostock supports the redefinition of “sex” to include “gender identity”, and that the decision requires the inclusion of transgirls/women in girls’ and women’s Title IX sport. Notably, however, they are inconsistent in their application of Bostock to the question whether administrators can lawfully distinguish biological females from males who identify as transgender. For example, in pending federal cases in Connecticut and Idaho, advocates for transgender athletes argue that their inclusion in girls’ high school sports must be full and unconditional, without regard to whether they are on gender-affirming hormones. However, in the Idaho matter, in which college sports are also at issue, they don’t challenge the NCAA rule, which distinguishes female athletes from transgender athletes by requiring males who identify as transgender to undergo a year of gender-affirming hormone treatments before they can compete in women’s sport. They support the position that in college, conditions on transgender inclusion are permissible. This distinction between high school and college may make good policy sense; but it is an acknowledgement of the continued lawfulness not only of the NCAA rule, but also more generally of what that rule represents, i.e., the lawfulness of distinctions on the basis of biological sex in sport. It is also a tacit acknowledgment of the fact that — as the Supreme Court itself announced — Bostock is not dispositive in this area.
A33. Formal sex-segregation in sport is the exception to general nondiscrimination law, requiring the exclusion of biological males from most girls’ and women’s sport. There is no case yet that finally resolves the question whether an exception to this general rule should be made for biological males who identify as women and girls. It is standard practice, however, for the courts to permit (and sometimes even to require) accommodations when there are good reasons for doing so, and when this is possible without imposing an undue burden. Thus, accommodations that would allow males who identify as transgender to compete in girls’/women’s sport should be permissible so long as they do not reduce participation, scholarship opportunities, or fair and safe competition for females.
III. ABOUT POLICY AND SOCIETY
A34. The principles that guided the Working Group in the development of its approach to males who identify as transgender in girls’/women’s sport are the following:
1. Women’s sport is designed to provide a space where biological females – whatever their gender identity – can compete only against each other and not also against biological males—whatever their gender identity. The design is based in compelling data and scientific evidence on the immutable performance gap between male athletes and female athletes. This separate-sex space should be preserved and affirmed. Girls’ and women’s participation in competitive sport nurtures individual health and development, contributes to the welfare of the community, and powers society’s perception of the strength and value of women and girls.
2. Males who identify as transgender are biologically male and so per the design would normally be excluded. However, because their inclusion could also produce real value both for the individuals concerned and for society, we should work to avoid unnecessary distinctions and exclusions. Therefore, equitable and inclusive accommodations for males who identify as women; gender-fluid athletes; and nonbinary athletes should be encouraged, so long as those accommodations do not diminish females’ sport opportunities or financial rewards, nor females’ right to fair, safe, sex-separated sports experiences.
3. Physical sex-linked differences between males and females are largely determined from the onset of male puberty but also have an impact on pre-puberty competitive sport. It is these differences that justify separate-sex competitive sport, and thus, they must be taken into account in developing responsible policy for girls’ and women’s sport.
4. Protocols for co-ed sports are instructive, as is the related tradition in law and policy of looking for ways to include rather than to exclude when this is possible without doing harm to an otherwise valuable institutional design. Being transgender does not change the fact of one’s biological sex. Where it is recognized in existing co-ed sports policy that sex is relevant to fairness and safety, it cannot be ignored simply because an individual identifies as transgender. Similarly, where existing co-ed sports policy recognizes that sex is not relevant to fairness and safety, the goal should be unconditional inclusion.
5. Specifically rejected as guiding principles are the unscientific, politically-driven mantras that claim that:
- “sex-linked differences including testosterone levels are indistinguishable from other differences like height, weight, wingspan, and foot shape”;
- “the performance gap between male and female athletes is based in myth, stereotype, and cultural inequities”;
- “the physical legacy advantages associated with developing as a biological male don’t exist or matter to sports performance”;
- “there is no evidence that transwomen and transgirls have a competitive advantage over females”; and
- “females only have the right to participate not to win”.
These patently false claims have no place in a serious discussion of the policy question whether and how to include transgender athletes in girls’ and women’s sport.
A35: Yes. We have publicly opposed these efforts and sought to work with like-minded state legislators of both parties toward law that would assure the accommodation of males who identify as transgender in girls’ sport in ways that are not female category defeating. We must develop equitable and inclusive accommodations for males who identify as women; gender-fluid athletes; and nonbinary athletes, so long as those accommodations do not diminish females’ sport opportunities or financial rewards, nor females’ right to fair, safe, sex-separated sports experiences. Also, we want to be sure opportunities for females who identify as transgender are similarly accommodated in boys’ sport.
A36: In all cases, female and male athletes have a right to privacy and must be provided with safe, private places to change clothes and shower. Neither male nor female athletes should be asked or required to share hotel rooms or other overnight accommodations (such as bedrooms in private homes) with members of the other sex, regardless of how those people identify. Females have not abandoned their legal right to privacy from males. Separating women and men in locker rooms is a nearly universal phenomenon, a custom that female athletes have come to expect and rely upon. Women are vulnerable when undressing. Criminal laws have protected women from male voyeurism for hundreds of years. Because women know that men are far more likely than women to commit sexual assault, the presence of males can be inherently threatening, even traumatic, to women as they are undressing or showering.1
Naked men also make women vulnerable; exposing male genitalia is typically a criminal act of indecent exposure or flashing.2
1 Statistics on male violence against women remain stubbornly high. According to the FBI, Males are responsible for 97% of murder and non-negligent manslaughter, 96.8% of rapes, 96% of pedophilia cases. See “FBI Crime in the United States 2018.” According to RAINN, 9 out of every 10 victims of rape are female.
2 Most males who identify as transgender do not undergo surgery to remove their penis and testicles. According to three recent studies, only between four and sixteen percent of transgender people undergo genital surgery. Annys Sinn, six key takeaways from the Post-KFF survey of transgender Americans, Washington Post, March 23, 2023; Ian T. Nolan, Christopher J. Kuhner and Geolani W. Dy, “Demographic and Temporal Trends in Transgender Identities and Gender Affirming Surgery,” Translational Andrology and Urology, June 2019, pp. 184-190.
A37: They’re already competing and winning in almost every imaginable sport. Here is a partial list of male winners in women’s sports.