The issue of transgender athletes participating in sports has long been viewed as an issue affected by culture and politics instead of science. Many people are divided in their opinions on this issue, and some may even choose extreme stances. Identity politics play a huge part in this issue.
Having said that, I would like to suggest a more moderate solution to this debate. This article will primarily focus on the participation of transgender women in sports because there is already an ingrained and deep-seated belief that they have advantages over cisgender athletes as compared to transgender men.
Gap in strength of biological males and biological females
The gap between the strength of an average cisgender woman and that of an average cisgender man becomes apparent at puberty. This gap comes to around 10–50%, depending on how frequently each muscle is used, which muscles are used, and which sports a person participates in (Hilton & Lundberg, 2021). Most transgender people transition after puberty, and then undergo feminizing hormone therapy.
Hormone therapy includes testerone blockers and estrogen for transgender women to decrease testerone levels and produce feminine or masculine secondary sex characteristics to simulate puberty. Most transgender people possess the same testerone levels as cisgender people of the same gender as them. 5% of cisgender women have testosterone below 2 nanomoles per liter. In a recent research study of 250 non-athletic trans women, 94% of them had testosterone levels below 2 nanomoles per liter (Scharff & Wiepjes, et al). This is much lower than the cutoff standard in most major sports federations.
We must consider that, although there is a cutoff standard, different methods of testing will return different results. The IOC rule uses immunoassay testing, while World Athletics uses liquid chromatography mass spectrometry (LCMS). To make sense of the units, 10 nanomoles by immunoassay test is equivalent to 7.5 nanomoles by LCMS.
Transgender women maintain higher strength levels
With or without hormone therapy, transgender women still maintain higher strength levels than cisgender women. However, strength is only one of the few key factors that affect athletic performance. These factors include lean body mass, explosiveness, and endurance, and, depending on the sport, other critical skills like hand-eye coordination or flexibility.
The greater strength proportion of transgender women must be put into perspective. Even for sports like weightlifting that involve mostly strength, endurance is also a key factor. For running, transgender women have faster speeds than cisgender women without hormone therapy.
After two years of hormone therapy, this gap is narrowed down to 12% faster in speed. However, this difference is negligible for athletes (Roberts et al, 2021). To be an elite runner, an athlete must be at least 29% faster than an average person. The 12% does not pose much of an injustice to athletes.
Endurance levels of transgender women are affected
Besides strength, endurance levels are also affected by hormone therapy. During hormone therapy, testorone is either decreased or increased based on gender, which also leads to a decrease or increase in hemoglobin levels. The hemoglobin level of transgender people is no higher than that of cisgender people.
A review of twenty-four studies conducted on transgender women found that testerone suppressants reduced hemoglobin levels in transgender women to that of cisgender women (Harper et al, 1999 – 2021). Hemoglobin production is a major influence on the endurance level of a person. Since transgender women do not have higher hemoglobin levels than cisgender women, there is no advantage in the area of endurance.
Endurance is as important as strength while competing in a sport. While transgender women may have higher strength, they do not have higher endurance. Skills like flexibility or hand-eye coordination are not affected by strength or endurance. Hormone therapy and biological sex do not affect these abilities, and thus transgender women do not have advantages in them either.
Significant decrease in lean body mass
Some biological males have a larger body frame than women. That includes transgender women who have not yet undergone hormone therapy. Some biological males also have higher lean body mass.
This will affect sports like weightlifting or boxing, where the size and weight of a competitor is a significant detail in performance. On the other hand, transgender women who have undergone hormone therapy have only slightly higher lean body mass than cisgender women. Considering that their muscle mass decreases, the size of their body may also be reduced slightly.
Some transgender women may also have a smaller body frame from birth already. Numerous studies have reported a significant decrease in the lean body mass of transgender women undergoing hormone therapy (Suppakitjanusant et al, 2020). Furthermore, those sports often have weight classes which match competitors against others of the same size. Even though some transgender women athletes may have a slightly heavier body mass or larger body frame than average cisgender women, they will still be evenly matched against women in the same weight category.
Laurel Hubbard in the olympics
For an example of such transgender athletes, we should look to New Zealand’s Laurel Hubbard, who competed in the Tokyo 2021 Olympics. At that time, Hubbard weighed 130 kilograms, while China’s Li Wenwen weighed 150 kilograms, a whole twenty kilograms more than Hubbard. Clearly, not all transgender women athletes weigh more than their cisgender counterparts.
In addition, Hubbard lost to Li Wenwen, showing that transgender athletes do not necessarily have an advantage. Although Hubbard lost, she is a pioneer for transgender athletes around the world by being the first openly transgender woman to compete in the Olympics.
Disadvantages in certain areas
Trans women may even face certain disadvantages. Some transgender women with larger body frames may have reduced muscle mass and aerobic capacity after hormone therapy. Their quickness and recovery speed may be slower than usual.
As Joanna Harper puts it, ‘...it's like a big car with a small engine competing against a small car with a small engine’. Harper is a sports physicist who has advised the International Olympic Committee (IOC) and other sporting bodies on gender and sports. The idea that transgender women only have advantages is wrong.
Despite having weight classes in certain sports, in other sports like rugby, the safety of competitors may remain a concern. If an athlete with higher body mass tackles an athlete with lower body mass, they may both be severely injured. In this case, individual rules are needed.
Every sport has a different technique and different playing style. Every sport also has different rules. Injuries caused by falls may be common in contact sports like basketball but are not common in other sports like archery.
Rules on transgender athletes must be adapted to fit the playing style of the sport. For sports like archery or swimming, perhaps not many changes to the rules are required, but for safety’s sake, changes to the rules of sports like rugby are needed. One good suggestion brought up to World Rugby before is that a limit of one transgender woman per team be put on teams.
As Harper says on WebMD’s interview, ‘Because even if there was a 20% risk increase, when a trans woman tackles a cis woman, and I'm quite certain, it's not that big, if only one of 15 players on the field was trans, then only a very small percentage of the tackles would be made by a trans woman. In each match, you're looking at a very small increase in risk.’ Unfortunately, World Rugby did not take up the suggestion. However, there are currently no transgender women competing at international level.
The International Federation of Sports Medicine (IFSM), which represents 125,000 physicians in 117 countries, has said that none of the latest research supports a blanket ban on transgender athletes competing in sports (Rachel S. (2021, March 25)). Nonetheless, experts agree that each sport needs their own rules on transgender athletes competing. To quote Blair Hamilton: ‘“I’ve played women’s sport now for four years.
I’m not dominating the sport.”. Hamilton is a transgender woman who researches trans athletes at Britain’s Brighton University and plays in the seventh tier of British women’s football. Experts also agree that meaningful competition without overwhelming advantages is at the heart of sports. Left-handed tennis players are allowed to compete against right-handed tennis players despite their advantages, and a study has raised the possibility that one-third of elite female athletes have slightly higher testerone levels than other female athletes.
We do not leave them out of the competition, because they do not breach the adage of ‘meaningful competition’. Likewise, we should not leave transgender women out of sports without a good reason to do so. Instead, we should opt for an unbiased view of this issue and evaluate the solutions according to science.
1. Hilton, E.N., Lundberg, T.R. Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage. Sports Med 51, 199–214 (2021). https://doi.org/10.1007/s40279-020-01389-3
2. Scharff, M., Wiepjes, C. M., Klaver, M., Schreiner, T., T’Sjoen, G., & den Heijer, M. (2019). Change in grip strength in trans people and its association with lean body mass and bone density, Endocrine Connections, 8(7), 1020-1028. Retrieved Nov 22, 2021, from https://ec.bioscientifica.com/view/journals/ec/8/7/EC-19-0196.xml
3. Harper J, O'Donnell E, Sorouri Khorashad B, et al How does hormone transition in transgender women change body composition, muscle strength and haemoglobin? Systematic review with a focus on the implications for sport participation, British Journal of Sports Medicine 2021; 55:865-872.
4. Pichatorn Suppakitjanusant, Yuhan Ji, Mary O. Stevenson, Panicha Chantrapanichkul, R. Craig Sineath, Michael Goodman, Jessica A. Alvarez, Vin Tangpricha, Effects of gender affirming hormone therapy on body mass index in transgender individuals: A longitudinal cohort study, Journal of Clinical & Translational Endocrinology, Volume 21, 2020, 100230, ISSN 2214-6237, https://doi.org/10.1016/j.jcte.2020.100230
5. Tricia W. (2021, July 15) ‘Do Trans Women Athletes Have Advantages?’, WebMD: https://www.webmd.com/fitness-exercise/news/20210715/do-trans-women-athletes-have-advantages
6. Rachel S. (2021, March 25) ‘No science to back blanket ban on trans women in sport: study’, Reuters: https://www.reuters.com/article/us-world-sport-lgbt-trfn-idUSKBN2BG34Q
7. ‘Feminizing hormone therapy’ (2021, March 18) Mayo Clinic: https://www.mayoclinic.org/tests-procedures/feminizing-hormone-therapy/about/pac-20385096