It’s one of the most difficult, sensitive and controversial issues in sport, sparking red-hot debate among scientists, lawyers, athletes and politicians. Should trans women – biological males who identify as females – compete in female sports events?

In recent years, sports authorities have fudged the issue, torn between fairness and inclusivity. Rules change. Arguments rage. Did those in charge assume the trans community was so small (just 0.1% of the UK population identify as trans women) this issue wouldn’t have an impact? Or did they hope women would acquiesce? Should they prioritise the vulnerable 0.1%, or the already disadvantaged 50%?  

Whatever the reasoning, several high-profile cases have forced the issue. New Zealand weightlifter Laurel Hubbard, who transitioned in her 30s, became the first openly transgender woman to compete at the Tokyo 2020 Olympics. To trans women, Hubbard is a heroic pioneer. But Hubbard’s selection came after defeating 2018 Commonwealth champion Feagaiga Stowers of Samoa – a sexual abuse survivor whose success has inspired other female victims – in the 2019 Pacific Games.

In 2022, the 6ft 1in American transgender swimmer Lia Thomas beat Olympic silver medallist Emma Weyant to a National Collegiate Athletic Association title. And this year Austin Killips became the first trans woman to win a UCI women’s stage race. Are we witnessing progressive social justice or misogynistic sporting injustice?

Sharron Davies: “Why is women’s sport less important than men’s?”

The debate over gender dysphoria has now spilled into amateur sport, with some schools hosting mixed-sex sports days, and ParkRun allowing self-identification, enabling trans women to hold female records. To some, this is inclusive and compassionate. To others, it’s profoundly unfair.

Some referees have quit amateur rugby, fearing that trans women could cause injuries: research suggests male-on-female tackles increase injury risk by 20-30%.

In the chaos, extreme views thrive. Female athletes have suffered death threats and been called transphobes. Trans athletes have been unfairly thrust into the media spotlight or abused. Most trans women just want to play sport and to belong. To them, this is an issue of identity, inclusion and human rights. Most female athletes are sympathetic, but worry about safety, privacy, sporting opportunity and fairness.

The fight for a level playing field
In the trenches of this debate stands Olympic swimmer and fearless campaigner Sharron Davies. In her new book Unfair Sport, written with the Times journalist Craig Lord, Davies issues a forensically scientific account of why female athletes should never face the male biological advantage.

Davies, 60, who missed out on a gold medal to the state-doped, testosterone-enhanced East German swimmer Petra Schneider at the 1980 Moscow Olympics, is outraged that some female athletes are fighting testosterone’s competitive advantages again. She blames the International Olympic Committee (IOC). “They messed everything up,” she declares. “They should have said: we’ll have to base it on the science, and we’ll do the science first.” But no. “They threw women’s sport under the bus, and now we’ve been clawing it back.”

Some professional female athletes have lost medals, titles and opportunities. “Elite females that have given all of their life up to their training are being beaten by very mediocre male athletes,” says Davies. She fears women being excluded from their own sports. “They are absolutely petrified to voice their opinions, which is a disgusting situation for us to be in,” she says.

American cyclist Hannah Arensman quit, aged just 24, after racing trans women left her “angered, disappointed, overlooked, and humiliated.” Other female athletes are upset about sharing locker rooms with trans women. “Why is it that women and young girls are so disposable, and our rights are so less important than males?” asks Davies.

Sharron Davies: “Girls self-exclude because they can’t compete fairly”

At recreational level, Davies worries that females will have less chance to shine. “A lot of women and young girls are self-excluding,” she says. “And they’re already a very difficult demographic to keep involved in sport.” She gets calls from parents upset about mixed-sex sports days. “And not a single little girl had won a race. But what message are we sending to little girls? We’re telling them they’re just not worthy.”

Fathers tell her they have taken their daughters out of rugby matches rather than see them tackled by males. She also points to a “dereliction of duty” over safeguarding: “Recently we’ve had the British Summer (Swimming) Championships and we had a 65-year-old trans-identifying male who thought, you know, put a skirt on and a red wig and thought that it was okay to walk through the girls’ changing rooms.”

Sharron Davies: “We’re telling little girls they’re just not worthy”

Davies insists she has “immense empathy” for trans people: she knows children with gender dysphoria, she hopes everyone lives free of abuse and she insists: “I really genuinely, with all my heart, believe everybody should be able to do sport.”

But she echoes Dr Jon Pike, an expert in sports philosophy, in saying that sport should be safe, fair and inclusive – in that order. “You identify however you like, and you must be safe, and you must be accepted, but race with your biological sex because that’s what’s fair,” she says. As Davies puts it: our feelings don’t do sports; our bodies do sports: “You can’t throw all women, all over the world, under the bus because a very small minority are unhappy with the biological reality of the body that they’ve got.”

“I didn’t think it would affect me this much – but facts must trump feelings”

In the firing line
With grim predictability, Davies has suffered death threats and abuse, and lost work and income. Activists have called her children’s schools. Charities have cut ties. “I’ve been called anything just to shut me up,” she says. “It doesn’t work.”

Other athletes like Paula Radcliffe, Daley Thompson and Mara Yamauchi have backed her. And many trans women would be appalled at such intimidation. But it has felt like a lonely crusade, despite surveys of the public and athletes confirming a large but silent majority agree with her, with just 16% of Britons supporting trans women’s inclusion in female events.

“The abuse is misogynistic – Daley Thomson gets a fraction of what I get”

The writer Joanne Rowling and the academic Kathleen Stock have faced similar abuse. Davies thinks these attacks are meant to inflict financial harm and sap her will to fight.  

“I couldn’t do that. I just couldn’t. Literally, I just thought, no. There were all these injustices and I have a problem with it. And if I stay complicit, then I’m as guilty as everybody else. And, you know, sadly my mum passed away and she left me some money. She left her house and it was split between me and my two brothers – my twin brothers. And that money has kept my head above water. Bless her.”

Policy and policing
How did we get here? As a starting point, all sporting governing bodies decide their own eligibility rules, though they often follow guidance from the IOC. In 2003 the IOC issued new guidelines, which suggested trans women must have undergone sex reassignment surgery, provided legal recognition of their gender and undergone hormone therapy to suppress testosterone. But in 2015 they dropped the surgery rule and switched to long-term gender declaration and reduced testosterone levels of below 10 nanomoles per litre for 12 months.

However, scientists pointed out that the normal female testosterone range is just 0.52-2.4 nanomoles. World Athletics later lowered this requirement to 5, and the UCI – cycling’s governing body – to 2.5. But in November 2021, the IOC issued an unexpected statement, declaring there should be no assumption that a trans athlete has any unfair advantage. A global team of sports medical experts criticised the claim. Respected sports scientist Dr Ross Tucker described it as a “scientifically bereft policy guideline.”

But after some high-profile cases, and enhanced scientific analysis, the pendulum has now swung the other way. In October 2020, World Rugby banned trans women from female matches. In June 2022, World Aquatics barred any male who has experienced male puberty. In March 2023, World Athletics followed suit. But FIFA, football’s governing body, still decides on a case-by-case basis, and other sports remain open to trans inclusion. The debate continues.

“Women are built differently and bodies do sport, not feelings”

Mapping the male advantage
So what does the science say? The most decisive argument against the inclusion of trans women is the huge biological male sporting advantage.

Male athletes are typically 40% heavier, 30% more powerful, 15% faster and 25-50% stronger than females. “We don’t turn around with a weightlifter or a heavyweight boxer and say, well you’re a heavyweight boxer, but you feel like a bantamweight, so you can go in there and beat the crap out of someone that’s three stone, five stone, eight stone lighter than you,” says Davies. “And that’s my point.”

Research suggests males typically have 40% more upper-body muscle mass, 30% less body fat and 30% higher maximal cardiac output, as well as higher lung capacities, longer arms, bigger handspans and more fast-twitch muscle fibres. Male swimmers, for example, have an 11-13% advantage. “We win medals by hundredths of a second, right, so you can’t give away 10-11%,” says Davies. “That’s half the length of the pool!”

It is why Adam Peaty’s 100m breaststroke world record (56.88) is 13% faster than that of the women’s record-holder Lilly King (1:04.13). And why the boys’ under-15 athletics 100m sprint record (10.20) is faster than the elite adult female world record (10.49).

Some trans supporters have suggested these gaps are simply down to the better coaching and professionalism enjoyed by males. In fact, one study claimed there is “no direct or consistent research” which confirms trans women have any advantage. One paper even claimed that any extra strength and size retained after hormonal therapy offers no real advantage. But few experts accept this. And an Everest of scientific evidence proves that males enjoy a huge advantage.  

Trans supporters stress there will always be unfairness in sport, whether you’re lucky enough to be an 6ft 9in basketball player or a double-jointed gymnast. The equality-focused Human Rights Campaign insist “natural variations in physical characteristics are part of sports.” But while we all have our differences, this argument ignores the sheer scale of the population-wide male advantage, estimated at 10-50%, depending on the sport.

Other trans supporters sidestep the scientific debate all together, suggesting the trans population is so small they will never dominate female sport. Yes, some women may miss out, but most won’t. This is all just a transphobic scare story. “Show me the evidence that trans women are taking everyone’s scholarships, are dominating in every sport, are winning every title,” footballer Megan Rapinoe told Time. However, we are now seeing trans women win races. It only takes one trans woman to deny a female athlete victory, whether it is in a local bike race or an Olympic final. And one victory can change a life.

The undeniable traits of testosterone
A more reasonable scientific argument is whether trans women can diminish the known advantages of testosterone through hormone therapy. Research suggests treatment can indeed reduce strength and muscle size – but not by enough. A 2020 paper in Sports Medicine found that after 12 months there is little reduction to the 10-50% male advantage, with lean body mass, muscle area and strength dropping by only 5%.

Davies cites a 2022 study that showed trans women retained a 20% advantage in heart-lung capacity and strength after 14 years of treatment. A review by the UK’s  Sports Councils concluded that “testosterone suppression is unlikely to guarantee fairness between transgender women and natal females in gender-affected sports.”

Some trans women fairly point out that after hormone therapy they would be disadvantaged if competing against males. Post-therapy, might they be closer to female than male levels of performance? This is why Dr Joanna Harper, a scientist at Loughborough University and a trans athlete herself, has promoted the idea of “meaningful competition,” instead of “fair competition.” The idea is that any advantage retained by a trans woman after therapy “would be only one component of their unique makeup.” But Dr Jon Pike has called this argument “a snare and a delusion,” calling it “an attempt at conceptual engineering that should be resisted.”

Besides, many scientists scream that testing for testosterone is pointless anyway, because trans women are permanent beneficiaries of male puberty, during which males develop greater muscle mass, size, speed, red blood cell capacity, bone density, hand size and feet size. “You can’t change the body, you can’t change the lung capacity, you can’t change the size of your hands or your height,” says Davies.

Those who transition before puberty would have fewer advantages. But males gain testosterone exposure even as a foetus, and research suggests early life exposure to testosterone leads to “higher growth velocity” and leaves an “imprinting effect” on body size. That is why 9-year-old boys can typically sprint 9.8% faster, jump 9.5% further and do 33% more press-ups than 9-year-old girls. And the issue of puberty-blockers for children remains a hugely complex and sensitive medical, legal and ethical debate which goes beyond the remit of sport. Sporting bodies can only listen to any shifting medical, legal and ethical positions – then respond.

For now, the weight of scientific evidence suggests the inclusion of trans women in female sport is not fair – and may never be fair.

Equality and the law
A much thornier issue, however, is the legal argument. Can a trans woman be excluded for identifying as they choose? What about equality and human rights laws? Trans women could claim any exclusion is discrimination. But female athletes could claim that competition against males is unfair. Many experts insist this conflict can never be resolved. Even the Sports Councils Equality Group (SCEG) has admitted that “for many sports, the inclusion of transgender people, fairness and safety cannot co-exist in a single competitive model.” Hard decisions must be made.

What happens next will depend on the law and how it is shaped in years to come. At present, the UK Equality Act 2010 lists gender reassignment as a characteristic which has protection against discrimination. But as Davies points out, the law does allow for single-sex spaces in certain situations, such as in women’s shelters, hospitals and – yes – in sport. “We are allowed, by law, to have biological female-only spaces,” she insists. The Equality and Human Rights Commission has backed this assertion.

Here’s the detail: section 195 of the Equality Act says it is lawful to restrict the participation of trans women from female sports, where strength, stamina or physique are key factors, in order to uphold fair or safe competition. So it would be legal to exclude trans women from female swimming events, but possibly illegal to exclude trans women from female snooker contests, where strength is less valuable.

Few people know about this legal reality, and some activists reject it, hence the chaos. Davies is pressing the government to clarify the law. In 2010 “everybody knew what sex meant,” she says, but now the word has been “muddied.” “What we need is to put the word ‘biological sex’ in front of it and then we will have very strong sex discrimination cases. And once we’re there, I will not be letting these primary schools cheat these young girls out of their opportunities, believe me.”

Sport is already exclusive
It is hard not to sympathise with trans athletes who feel excluded. Many already face abuse and stigma. And any challenge to identifying as a female can erode their mental health or represent a barrier into sport. But there is one group missing from this debate so far: trans men. As Davies points out, almost all trans men (biological females who identify as men) and biological females who identify as non-binary still compete with women. “If these people can identify however makes them feel comfortable, but still compete with people of the same biological sex, why can’t males (who identify as trans women) do exactly the same thing?” she asks.

The truth is that sport always excludes in order to include. Most sports are categorised based on sex, age, weight and other factors. It is what stops a heavyweight boxer fighting a featherweight boxer. And what stops an able-bodied athlete entering the Paralympics. As Davies puts it: “There is no ‘trans ban’ any more than there’s a ban on me being in a race for 12-year-olds.”

These categories spread opportunity across society, with each group able to share in the striving and the success. “If we didn’t have sex categories, which is the biggest difference, young, strong men would win everything,” warns Davies.

“We must find space for everyone – an Open category is the answer”

Putting fairness first
One final – crucial – question is where sport chooses to draw the line between fairness and inclusivity. Some trans supporters say: forget the science, forget the law, let’s prioritise inclusivity. Indeed, in 2022, the UCI, cycling’s governing body, stated – astonishingly – that while all athletes should have a chance to succeed, it is “not necessarily an equal chance.” In other words, a slight unfairness to females could be tolerated, up to a point, in pursuit of inclusivity. This is the “meaningful competition” approach suggested by Dr Harper. Although nobody seems to have asked women.

A few athletes, at least, agree. “We need to start from inclusion, period,” Megan Rapinoe told Time. “Sport is not the most important thing in life, right?” Think about trans people. They already face higher rates of prejudice, violence, family rejection, discrimination, depression and suicide. Just let them play.

Some trans supporters add that at recreational level, at least, sport is about fun, not winning, so let inclusion trump fairness to help nurture a more inclusive society. But surveys – not surprisingly – suggest a huge majority disagree. And the victims of this approach are – and always be – girls and women. “I do not understand how women’s sport is so less important than men’s sport,” says Davies. “Men would never accept being asked to compete on an unfair playing field.” She adds that female athletes already get a small percentage of the ad revenue or TV coverage: “Our piece of the cake is already tiny.”

And so, we’ve come full circle: do we prioritise the feelings of the 0.1%, or fair sport for the 50%? Compassion, it turns out, is much more complicated than we like to believe. But without fair or safe competition, is sport even sport?

“I see my granddaughter and I have to live with myself so I have no regrets”

Finding a compromise?
Amid the confusion and indecision, many people have already suffered. Dr Tucker has said he dislikes the “unpleasant” tone that trans athletes are often characterised as cheats, rather than folk who just want to play sport. And female athletes who have spoken out, like Davies, have faced appalling abuse. “I knew it was going to affect me, but I didn’t think it would affect me quite so much, if I’m really honest,” reflects Davies. “But it is very toxic. It’s really difficult to have honest discussions about something that is a feeling. When we really need to be working with reality and honesty… because a feeling can’t trump a fact. It just can’t.”

In the future, a compromise will be required. “What we must do is find space for everyone, whether that’s creating extra categories or creating an ‘Open’ category, which I think is probably the answer,” says Davies. Swimming, cycling and triathlon have all announced plans for a ‘Men’s/Open’ category, to sit parallel to a protected female category, as a middle ground between protecting female sport and respecting the identity of trans women.

No solution will be perfect. If we introduce separate ‘trans’ categories, there may be too few athletes to sustain competition. What works at elite level may not work at amateur level: how will organisers of a small local bike race sensitively verify sex? And many trans women dislike the ‘Open’ idea too. But the more ideas and opinions, the better, says Davies. The problem is that, until now, debate has been stifled. “It’s beginning to turn because we’re allowed to now talk about it,” she insists.  

Davies is particularly upset at the silence of male athletes on this issue. “We need men to stand up for women,” she says. “We need the men to go: we’ve got wives, daughters, sisters, mothers. We need them to have a voice. Because a lot of them think this is not their problem but it is their problem.”

However, above all else, Davies hopes women find their voice – and are respected. “Somehow women are told to be kind,” she sighs. Surveys suggest 61% of the British public object to trans women in female events, with just 16% in support. And a survey of British Rowing members found that 80% want fair female sport. “The female voice has just been ignored in so many instances,” concludes Davies. “And I do believe in years to come, we will look back in this period of history and think: what on earth were we doing?”

Unfair Play by Sharron Davies and Craig Lord is out now