The effect of testosterone on sporting performance

Doriane Coleman is a professor of law at Duke Law School. She specialises in the differences between biological sex and gender identity. She is also a former champion runner.

In a very long and detailed article (worth taking the time to read it all) she makes some insightful points:

The female range for testosterone is categorically different from the male range. In general, males have 10 to 30 times more T than females. Most females, including most elite female athletes, have T levels in the range of 0.5 to 1.5 nanomoles per liter (nmol/L). For men, typical values are 10 to 35 nmol/L. The reason there is a gap, with no overlap between the ranges, is that beginning in puberty, the testes produce a lot more T than ovaries and adrenal glands combined. And so the IAAF maximum of 5 nmol/L for women has been set, generously, to reflect the upper bound of T levels that can be produced even by polycystic ovaries.

That is one key aspect. There is no overlap between the normal range for women and men. Not even close. This isn’t something like height where many women are taller than than many men. No biological adult woman has a testosterone level higher than the lowest level in a biological adult man. The top of the range for a woman is around one quarter the bottom of the range for a man.

For example, as my colleague Wickliffe Shreve and I have shown, just in the single year 2017, Olympic and World Champion Allyson Felix’s lifetime best in the 400 meters of 49.26 seconds was surpassed over 15,000 times by boys and by men.

Some people may think that having male levels of testosterone may just give you a slight advantage. But thousands of men and boys can beat a female world record shows the advantage is huge.

Even non-elite male-bodied athletes, including boys, can and do routinely surpass the very best female athletes.

This is why having male levels of testosterone is seen by many elite female athletes as giving them no chance at all.

To be clear, our claim is not that an identity-based eligibility rule would introduce this enormous sea of boys and men into women’s competition. Rather, it’s that biologically male athletes—however they identify—don’t have to be elite to surpass even the very best biologically female athletes. And it doesn’t take a sea of them to obliterate the females’ competitive chances at every level of competition. If only a very small sub-set turn out to identify as women, we will be overwhelmed. …

They say that testes and T levels in the male range should be treated like other special traits that sport properly celebrates. Accordingly, Ms. Semenya is special because she is a woman with testes, just like Missy Franklin is special because she is a woman with an unusually large wingspan. As an academic, I’m familiar with the game that is deconstructing established truths and then re-imagining the world differently. But this isn’t the academy and it isn’t a game. In the real world, the analogy has no merit.
Sport has never sought to celebrate testes as special in either the men’s or the women’s category. Precisely the opposite is true: Gonadal sex traits define the categories, and then each separate category sets out to isolate and celebrate other characteristics. In the men’s category, testes and male T levels are perfectly normal and not at all special. Every single male in the category has them, and so the category isolates and celebrates different traits, like height and wingspan. And the women’s category was developed to exclude competitors with testes and T levels outside of the female range, so that biological girls and women could have the chance—as biological boys and men do—to have their equally exceptional but non-gonadal traits isolated and celebrated. It is within the categories that a Usain Bolt and a Katy Ledecky are properly held out as indomitable superstars.

A nice debunking of that argument.

Ms. Semenya is an extraordinary person. She is courageous, resilient and dignified. And as my longtime colleague Edwin Moses wrote recently in Time magazine, which featured her as one of its 100 most influential people of the year, “Caster Semenya has taught us that sex isn’t always binary, and this has caused us to question the merits of distributing societal benefits according to ‘male’ and ‘female’ classifications…however [her case comes out], Semenya will have already made a singular historical contribution to our understanding of biological sex.”
It is beyond doubt that this road has been a difficult one for her to travel. It was difficult for me to bear witness to her process—even as she remained unbelievably gracious throughout. Still, we must recognize that the underlying issue also has caused extraordinary harm to the females in the field; to the women’s middle distances, including their commercial and developmental aspects; and to the IAAF, which has expended significant resources trying to protect the women’s category for its intended purposes.

Semenya is extraordinary. It is not her fault she was born intersexual and it is awful she has had to endure such publicity. But as the author makes clear the decisions affect all female elite athletes.

At the non elite level, participation based on gender identity is of course what should happen. But at the elite level, not having some sort of biological test makes different gender competitions potentially meaningless.