The International Olympic Committee (IOC) guidelines that allow male-to-female transgender athletes to compete in the women’s category at the elite level has raised significant debate since their introduction in 2015.

New research has been undertaken by a group of Otago University professors who suggest that it is time that existing gender categories in sport be abandoned in favour of a more ‘nuanced’ approach when it comes to the inclusion of transgender athletes. Tuwhenuaroa Natanahira spoke with Professors Lynley Anderson and Alison Heather about their research.

Lynley Anderson is an Associate Professor in Bioethics at Otago University. She is an expert in clinical ethics.

Alison Heather is a Professor in Health Science at Otago University. She is an expert in sex hormones and atherosclerosis.


This interview has been edited for clarity and length 

Tuwhenuaroa Natanahira: What are the current IOC guidelines around the inclusion of transgender athletes?

Lynley Anderson: In 2015, they were changed. Prior to that trans athletes had to have gender affirmation surgery. In 2015, that went, that is no longer required, the new requirements are that the testosterone levels have to be under ten nanomoles per litre for one year. So they have declared for sporting purposes their gender to be female for at least four years and their blood testosterone levels are below ten nanomoles for at least twelve months prior to competition. So that is what the 2015 guidelines state. And that is a change from 2004 when you had to have gender affirmation surgery.

TN: Why did you conduct the research in the first place?

LA: Probably because we were thinking about the fact that there are two principles at play here. One of them is the principle of fairness and the other one is the principle of inclusion. And we could see that some of the ways in which the IOC have set things up have been more about fairness and sometimes it has been more a bit about inclusion, and I think there has been a lack of understanding of the need to balance these two competing principles.

TN: What kind of changes would you propose to the current IOC guidelines?

LA: It is hard because the IOC are in a difficult position trying to write these guidelines, but what we are proposing is perhaps we should stop trying to push and squeeze people into just two categories. Maybe we should rethink the structure of sport so that it can accommodate people of all different types. Maybe we should be thinking and reconsidering the gender binary. And so we are suggesting something more nuanced than the gender binary currently allows for.

TN: What has your research found?

Alison Heather: The research is showing that trans female athletes have a prior male physiology, and what we mean by that is that we can’t just simply take the testosterone level in the here and now, but we have to consider their exposure to testosterone over their entire lifetime. So testosterone even in utero is predisposing male brains to be more competitive and more aggressive which then leads to competitive advantages later in life. It is also setting them up to have bigger bone structure and a different bone structure that can help with some sports, it helps them have more muscle mass which again will help with athletic performance. It also sets them up to have a more efficient cardiovascular and respiratory system, again all of this contributes to athletic performance. So when a trans female transitions to a female by taking estradiol therapy to lower their testosterone levels, none of the male physiology that had existed since they were a foetus goes away. So while the testosterone level is lower the fact they have had that testosterone level for so long is not mitigated by the estradiol therapy, and this includes muscle mass and bone strength.

TN: Why did you decide to conduct the research?

AH: Initially it was about looking at trans female athletes and how they were starting to dominate some female sports. It was about looking at the fairness issue and would all that prior male physiology be mitigated by hormone therapy and if it is not then what is that percentage difference between a female athlete and a trans female athlete. So if we look at world records, male athletes completely dominate female world records, there is a ten percent difference in endurance sports, there is up to thirty percent difference in sports that rely on strength. So if we consider that, a trans female athlete has to lose basically thirty percent of her prior athletic advantage to be competitive against females who are biologically born female. It is very hard to see how a thirty percent difference can be taken away by simply have estradiol therapy.

TN: What changes do you propose to the current IOC guidelines?

AH: First of all, I would like to see the IOC guidelines lowered so the testosterone levels should not be at ten nanomoles anymore. This is at least tenfold higher than a female athlete. The other thing I would like to see is the length of time changed for the estradiol therapy, at the moment it is just one year and there is evidence that shows after one year there isn’t enough mitigation in muscle mass and other physiological factors so it should be extended out at least beyond a one year period. And finally, I would like to think that society could really try to embrace diversity and that instead of trying to force everyone into a male and a female box that we could instead create divisions where gender diverse people could be competitive and feel like they are competing in a safe space.

TN: You considered some possible solutions in the research and they include excluding trans athletes from competing in a women’s division, creating a third division for trans women and intersex women, and calculating a handicap for trans women based on their testosterone levels. Do you think that is counter-productive in a sense that they have transitioned so they are now women?

AH: Socially they are women but they still would not be considered a biological female. So we have to make that division between what society accepts as a woman compared to scientific ideas of a biological female. And I think that is where the debate is arising.

This interview was originally aired on The Wire. To hear the audio and download this interview click here.

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See Also:

Caster Semenya: Is bogus science being used to stifle the vulnerable?

Double faults and double standards: Why are women not treated equally in sport?