Joanna Harper on the Performance of Transgender Athletes

Joanna Harper, researcher on the performance of transgender athletes

Joanna Harper has a master’s degree in physics and several years of experience working as a medical physicist. After her gender transition in 2004 and subsequent reduction in running speed, she turned her focus to the performance of transgender and intersex athletes. In 2015, she published the first peer-reviewed article containing quantitative analysis of the athletic performance of transgender athletes with differing hormonal values. Since then, she has collected subsequent retrospective data on transgender athletes and is currently engaged in a prospective analysis of two transgender athletes.

Harper is the author of the book Sporting Gender: The History, Science and Stories of Transgender and Intersex Athletes. She has authored articles on gender diverse athletes in both peer-reviewed publications and in the Duke University Law Review. Harper has served as an advisor on transgender and intersex athletes to multiple sporting federations including the International Olympic Committee since 2015. In the fall of 2019, Harper relocated to Loughborough University, where she is now engaged full-time in the study of transgender athletic performance.

In this interview, Joanna and I discuss her research on the performance of transgender athletes and how sports governing bodies can address this issue in a fair manner.

Greg: What was your transition experience like? Were there different considerations for you personally versus athletically?

Joanna: My transition was the most difficult thing I ever did, but the most personally rewarding thing as well. On a personal level, I got divorced over my transition and I wound up with a very strained relationship with my mother.

When I first started my transition, I didn’t know if I would ever get to officially race in the women’s division, so that was a major issue.

If you want more detail, I would direct you to Chapter 8 of my book Sporting Gender.

Joanna Harper competing in a cross country race

Greg: You’ve published research on the performance of transgender athletes versus cisgender athletes. What did that research show?

Joanna: I published a study looking at race times of eight trans women on either side of transition. The study reported that the athletes’ performance times were more than 10% slower after hormone therapy (HT). The race times were then compared using a methodology known as age grading, a statistical method used to factor out the reduction in performance as part of the aging process. There was no meaningful difference between the age grade scores of the distance runners before HT when they were being compared to male runners and the age grade scores after HT when they were being compared to female runners.

The age-graded equivalency of the race times indicates that the runners were approximately equally competitive in the men’s division prior to and in the women’s division after HT. This finding cannot be generalized to all athletes in all sports. Performance levels in endurance sports are strongly correlated to hematocrit which changes from male to female levels with HT. On the other hand, size and strength are not especially advantageous in endurance events but are important factors in success in other sports.

Greg: We’re in the early stages of learning about the performance of transgender athletes. What additional questions need to be answered by the governing bodies of sports?

Joanna: We need to look at the performance of transgender athletes in a number of sports, in a similar manner to my first study. We also need to get trans athletes into sports performance labs and see what happens to them as they undergo HT. I am of the firm opinion that individual sports governing bodies need to come up with sport-specific rules governing elite athletes.

Greg: Is there any research on the performance of intersex athletes?

Joanna: There is one paper (Bermon, 2017) that indicates a 5.7% reduction in the performance of three intersex athletes once they went on testosterone-suppressing drugs. I coauthored (Harper et al., 2018) a paper looking at the over-representation of intersex athletes*, as did Stéphane Bermon (Bermon et al., 2013). World Athletics presented additional data to the Court of Arbitration for Sport panel in the Caster Semenya case, but they will never publish it over privacy concerns. Getting data on trans athletes is challenging enough, but the trans population is 100 times the size of the population of people with XY differences in sexual development.

Greg: Last week, the U.S. Education Department decided that Connecticut’s policy allowing transgender girls to compete as girls in high school sports violates the Title IX civil rights of athletes who have always identified as female. What are your thoughts on this decision? How should sports governing bodies handle transgender athletes? Should those policies differ between the professional and amateur levels?

Joanna: In fact, the Department of Education went further than you suggest. The Department claimed that allowing trans women to compete against cisgender women (under any circumstances) violated Title IX. They did only threaten Connecticut with the withdrawal of federal money. I don’t actually agree with the Connecticut state rules (I don’t think that gender identity should be the basis to divide athletes into male and female categories), but I think that allowing trans women into women’s sports (with certain restrictions) should be allowed. This case, however, is being heard by a federal court, and the opinion of the Department of Education is not the deciding factor. We shall see what the court decides.

I think that for high-level sports we should separate athletes into male and female categories using a biomarker (or biomarkers) that is (are) important to differentiate male athletic performance from female athletic performance and is (are) mostly dimorphic. Given the 2020 level of science, testosterone is the best available biomarker. When it comes to recreational sports, we should let athletes compete in whichever category they feel most comfortable.

*-Intersex athletes are over-represented at the elite levels of track and field, meaning that the percentage of intersex individuals in these events is greater than the percentage of intersex individuals in the general population.