Trans women’s bodies have been thrown into the spotlight recently. With a private member’s bill which “seeks to exclude trans girls and trans women from participating in sports” in the Senate being supported by some in government, and fervently denied by others, it’s worth diving into the science behind the issue causing all this furore.
While research in this field is still in its infancy, it’s clearer than some think. Not only do trans women not have advantages over cis women in sport in most cases, but cis women playing sports are overwhelmingly not worried about trans women competing alongside them.
First, let’s start with the science. When a trans woman decides to transition, usually one of the first medical steps they’ll undertake is to go on hormones. These are testosterone blockers (also known as anti-androgen medications) and estrogen, both of which are common medications that can also be prescribed to cis women to treat various ailments.
These hormones have a number of effects on a trans woman’s body – they add and change the way fat is distributed, they lower the levels of red blood cells, and significantly decrease strength, muscle and lean body mass.
“In sports cheating via ‘blood doping’, red blood cells are raised,” wrote Ada Cheung, an endocrinologist from the University of Melbourne, in a Sydney Morning Herald opinion article. “The opposite occurs in trans women: oxygen-carrying red blood cells drop to female levels. Trans women gain fat mass and lose bone density.
“Further research is coming. My research group at the University of Melbourne, in collaboration with the Institute for Health and Sport at Victoria University, have started the GAME research study examining how feminising hormones impact fitness, endurance, physique and gene changes in muscle over time in comparison groups.”
Although hormones will change many facets of a trans woman’s body if they transition as an adult, it won’t change someone’s height; and one study, published in the British Journal of Sports Medicine, suggested that despite strength and muscle decreasing, they may still have a small advantage over the average cis women.
This is where the controversy comes from. Is it “fair” for someone who went through male puberty to be able to play at the elite level with women? Despite the recent coverage, this is not a particularly new issue. In elite sports, many sporting bodies already have codes in place that allow trans women to play if their testosterone level is below 5–10 nanomoles per litre for a number of months.
More on inclusivity in sports: Transgender runners at no advantage
But in almost all sports, height or a slight strength advantage are not what gives you the leg-up over competitors. The AFL has called the ideas that trans women will “dominate” on the field, or cause a safety concern to their cis teammates, as “myths”.
“Sporting ability is more than just hormones,” they write in their Gender Diversity Policy. “Like other players, gender diverse players are all individuals and may have a range of physical abilities, fitness, skill levels and different strengths and weaknesses in the multi-skilled game of Australian football.
“For example, a cisgender or transgender woman may be taller and/or stronger than other women competitors but may also be slower and/or less agile.”
The results at the Olympics and other major sporting events back this up. For the very few trans women who have competed in sport at the elite level, there’s been no domination over cis women. Trans women may occasionally win, but they have never broken a world record, or won an Olympic event. If anything, trans women seem very much on an even playing field with their cis counterparts.
It’s also worth pointing out that the cohort of trans girls who transitioned before going through male puberty is only going to increase as more transgender people are able to transition earlier. For example, in 2017 in Australia, a law was overturned in the courts that had required all under 18 trans youth to go to court to be able to access puberty blockers or hormones from their doctor. Although there’s still a long way to go, increased access to gender affirming care for kids means that the issue itself is very likely to get smaller over time.
This idea that trans women are naturally better at sport than cis women comes back to the impression that men have an innate advantage over women in every sport, which is not true either. Although we’ve mentioned that men are on average taller and stronger than women, at very long distances in ultra-running, research has shown that women start to outcompete men. This seems to be because women are metabolically better suited for endurance. Then there’s sports like figure skating, which became segregated in 1905 after British woman Madge Syers entered what had previously been an all-male World Championships and won silver.
But in the debate on the inclusion of transgender women in sports, we are not just talking about elite sport – this also includes community and children’s sports, both which involve a different range of issues.
The vast majority of sports are played by those who are kids and teenagers, and the highest percentage of people who identify as transgender are people under the age of 18. It’s important to acknowledge that trans women in sport includes trans girls who have never gone through male puberty – and who could benefit from the health and mental wellbeing benefits of sport the most. Unfortunately, the data shows that LGBTQ+ people are under-represented playing sports.
“Sport is a very valuable tool to be used to help boost LGBT kids’ self-esteem and self-worth,” says Erik Denison, the lead researcher at the Sport Inclusion Project at Monash University.
“Everything we know from the Centres for Disease Control and Prevention (CDC), in the US, is that if kids play sport, they’re about half as likely to have attempted suicide in the last year.”
Many community women’s clubs do not have testosterone guidelines and welcome anyone who identifies as a woman. On top of that, research surveys done by Denison have also shown that the majority of women sporting players do not see playing against a trans competitor as an issue.
In his research across six sports and 12 community clubs at Monash University, less than a quarter (24%) of women believed “trans women have an unfair advantage when they play on a female sport team”. Interestingly, when men were asked the same question, that percentage almost doubled (46%). This is similar to other research findings around the world.
Denison understands this. When he first began work in this field, he also assumed that trans women would have an unfair advantage. The research has changed his understanding, but it’s worth noting exactly why this difference exists.
“For [men] playing sport, the number one reason is about competition and winning,” he says. “I’ve never done research where the first thing a guy says is that they like their sport because it’s inclusive or welcoming or friendly,” he says.
“Whereas just about the first thing every woman that I’ve ever interviewed says when you ask them, ‘Why do you like your sport?’ is, ‘Oh, it’s great to meet friends, it’s inclusive, it’s a very friendly club’.”
This echoes my own experience playing in a women’s AFL team with trans women playing alongside us. And this inclusive, welcoming aspect goes back all the way to when women’s sports were just beginning to rise in popularity in Australia.
“There are lots of examples where women created their own associations, leagues and competitions because if they didn’t, they simply would not have had the opportunity to play,” explains Kirby Fenwick, co-founder of Siren: A Women in Sport Collective and an expert in the history of women’s sport.
“Men have long dominated sport in Australia and too often resisted creating space or opportunity for women. “Embedded in the fabric of women’s sport is a foundation of community and inclusivity – a desire to bring people in, not look for ways to keep them out.”
This article first appeared in Cosmos Weekly on 6 May 2022. To see more in-depth stories like this, subscribe today and get access to our weekly e-publication, plus access to all back issues of Cosmos Weekly.
Jacinta Bowler is a science journalist at Cosmos. They have a undergraduate degree in genetics and journalism from the University of Queensland and have been published in the Best Australian Science Writing 2022.
Read science facts, not fiction...
There’s never been a more important time to explain the facts, cherish evidence-based knowledge and to showcase the latest scientific, technological and engineering breakthroughs. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science. Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today.