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Trans women in female sports: A sports scientist’s take

An interview with Ross Tucker, PhD


 

When Lia Thomas won the women’s 500-yard freestyle at the 2022 NCAA Division 1 swimming championships, the issue of trans women’s participation in female sports ignited national headlines.

This news organization interviewed Ross Tucker, PhD, an exercise physiologist from South Africa, who was involved in the World Rugby Transgender Guidelines, which prohibit trans women’s participation.

This interview has been edited for length and clarity.

Let’s start with the proinclusion argument that there are always advantages in sports.

That’s true. The whole point of sports is to recognize people who have advantages and reward them for it. By the time this argument comes out, people have already accepted that males have advantages, right?

Some do, some don’t.

If someone uses this argument to say that we should allow trans women, basically biological males, to compete in women’s sports, they’ve implicitly accepted that there are advantages. Otherwise, what advantage are you talking about?

They would say it’s like the advantage Michael Phelps has because of his wingspan.

To answer that, you have to start by asking why women’s sports exist.

Women’s sports exist because we recognize that male physiology has biological differences that create performance advantages. Women’s sports exist to ensure that male advantages are excluded. If you allow male advantage in, you’re allowing something to cross into a category that specifically tries to exclude it. That makes the advantage possessed by trans women conceptually and substantively different from an advantage that’s possessed by Michael Phelps because his advantage doesn’t cross a category boundary line.

If someone wants to allow natural advantages to be celebrated in sports, they’re arguing against the existence of any categories, because every single category in sports is trying to filter out certain advantages.

Weight categories in boxing exist to get rid of the advantage of being stronger, taller, with greater reach. Paralympic categories filter out the natural advantage that someone has if, for example, they are only mildly affected by cerebral palsy, compared with more severely affected.

If someone wants to allow natural advantages, they’re making an argument for all advantages to be eliminated from regulation, and we would end up with sports dominated by males between the ages of 20 and 28.

There are some people suggesting open categories by height and weight.

The problem is that for any height, males will be stronger, faster, more powerful than females. For any mass, and we know this because weightlifting has categories by mass, males lift about 30% heavier than females. They’ll be about 10%-15% faster at the same height and weight.

There’d be one or two sports where you might have some women, like gymnastics. Otherwise you would have to create categories that are so small – say, under 100 pounds. But in every other category, most sports would be completely dominated by males.

It’s not a viable solution for me unless we as a society are satisfied with filtering out women.

Another argument is that if trans women have an advantage, then they would be dominating.

That one misunderstands how you assess advantage. For a trans woman to win, she still has to be good enough at the base level without the advantage, in order to parlay that advantage into winning the women’s events.

If I was in the Tour de France and you gave me a bicycle with a 100-watt motor, I wouldn’t win the Tour de France. I’d do better than I would have done without it, but I wouldn’t win. Does my failure to win prove that motors don’t give an advantage? Of course not. My failure says more about my base level of performance than it does about the motor.

In terms of trans athletes, the retention of biological attributes creates the retention of performance advantages, which means that the person’s ranking relative to their peers’ will go up when they compare themselves to women rather than men. Someone who’s ranked 500 might improve to the 250s, but you still won’t see them on a podium.

It’s the change in performance that matters, not the final outcome.

Wasn’t Lia Thomas ranked in the 500s in the men’s division?

There’s some dispute as to whether it was 460 or 550 in the 200- and 65th in the 500-yard freestyle. But the concept is the same and we can use that case because we know the percentage performance change.

As Will Thomas, the performance was 4:18 in the 500-yard freestyle. As Lia Thomas, it’s 4:33. Ms. Thomas has slowed by 5.8% as a result of testosterone suppression. That’s fairly typical; most studies so far suggest performance impairments in that range.

The thing is that the male-female gap in swimming times is 10%-12% on average. That means that Ms. Thomas has retained about half the male advantage.

In strength events, for instance, weightlifting, where the gap is 30% or more, if you lost 10%, you’d still retain a 20% advantage and you’d jump more ranking places.

The retention of about half the male advantage is enough for No. 1 in the NCAA, but it’s not enough to move Ms. Thomas to No. 1 in the world.

The record set by Katie Ledecky in the 500 freestyle is 4:24. Thomas swam 4:18 as a man so could only afford to lose about 1% to be the record holder in women’s swimming.

When Ms. Thomas was beaten by cisgender women in other events, your point is that’s just because her baseline (pretransition) time wasn’t good enough.

Exactly. Are your performances in men’s sports close enough to the best woman such that you can turn that retained advantage into dominance, winning in women’s sports?

If the answer to that is yes, then you get Thomas in the 500. If the answer to that is not quite, then you get Thomas in the other distances.

On your podcast, you expressed frustration at having to keep debunking these arguments. Why do you think they persist?

There are a few things in play. There are nuances around the idea of advantage that people from outside sports don’t always appreciate.

But then the second thing comes into play and that’s the fact that this is an emotive issue. If you come to this debate wanting trans inclusion, then you reject the idea that it’s unfair. You will dismiss everything I’ve just said.

There’s a third thing. When people invoke the Phelps wingspan argument, they haven’t thought through the implications. If you could sit them down and say: “Okay. If you want to get rid of regulating natural advantages, then we would get rid of male and female categories,” what do you think would happen then?

They may still support inclusion because that’s their world view, but at least they’re honest now and understand the implications. But most people don’t go through that process.

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