Why Measuring Testosterone Makes Sense

Sex, Sport, and Why Track and Field’s New Rules on Intersex Athletes Are Essential

Image
Because of testosterone throughout the life cycle, many nonelite males routinely outperform the best elite females, including in track and field.CreditJonathan Ferrey/Getty Images

By Doriane Lambelet Coleman

April 30, 2018

Last week, track and field’s world governing body limited entry into women’s events to athletes who have testosterone levels that are capable of being produced solely by ovaries.

These rules apply across the board to athletes however they presented at birth. Advocates for intersex and transgender athletes have vigorously attacked the International Association of Athletics Federations’ new rules, but they are an extraordinary compromise for women’s sports, including for traditional feminist proponents of equal access to sports for girls and women, guaranteed in the civil rights legislation known as Title IX.

Understanding the rules and why they make sense is hard. They are based in biology people don’t know or don’t like to talk about and, let’s be honest, at least in some circles, they’re politically incorrect. They force us to talk about women’s bodies when it is increasingly taboo to do so, and they run counter to the movement that seeks to include transgender and intersex people in social institutions based on their gender identity rather than their biology.

These are important progressive developments, but their effects on valuable institutions like women’s sport are real and they need to be understood before positions harden on bad information. Pretending that the female body doesn’t exist or that we can’t define the boundaries between men’s and women’s bodies is a bad idea for many reasons. Replacing traditional sex classifications with classifications based on gender identity certainly has steep costs in contexts like competitive sport, where the likelihood of success is precisely about sex-specific biology.

A lot has been written about intersex athletes who identify — or are identified in their legal documents — as women. What is important to know is that there are many different intersex conditions, but the I.A.A.F. is only concerned with the subset that involves athletes who are biologically male. They are “in between” only with respect to the pre-birth underdevelopment of their external genitals. Intersex athletes who are biologically female aren’t affected by the rules.

Specifically, the athletes who are the focus of the I.A.A.F.’s rules are those who have testes. Starting in puberty and as adults, their testes produce sperm, not eggs, and supply testosterone in quantities that biologically female bodies and their ovaries never come close to producing.

The male range at its lowest is three times higher than the female range at its highest. At puberty these athletes developed male, not female, secondary sex characteristics: increased muscle mass and strength, including increased heart size; higher hemoglobin levels, which result in better oxygen carrying capacity; and different muscle types and ratios of fat to muscle.

Advocates for intersex athletes like to say that sex doesn’t divide neatly. This may be true in gender studies departments, but at least for competitive sports purposes, they are simply wrong. Sex in this context is easy to define and the lines are cleanly drawn: You either have testes and testosterone in the male range or you don’t. As the I.A.A.F.’s rules provide, a simple testosterone test establishes this fact one way or the other.

Testosterone throughout the life cycle, including puberty, is the reason the best elite females are not competitive in competition against elite males. This 10- to 12-percent sex-based performance gap is well documented by sports and exercise scientists alike. But it isn’t the most important performance gap. Rather, that’s the mundane fact that many non-elite males routinely outperform the best elite females.


Each year, the world’s best time in the women’s marathon is surpassed by hundreds of men. The women’s world records in all of the races on the track from 100 meters to 10,000 meters are also surpassed by many men each year, including by many high school boys. For example, in 2017, 36 boys ran faster than Florence Griffith Joyner’s seemingly unassailable 100-meter record of 10.49.


There is no characteristic that matters more than testes and testosterone. Pick your body part, your geography, and your socioeconomic status and do your comparative homework. Starting in puberty there will always be boys who can beat the best girls and men who can beat the best women.


Because of this, without a women’s category based on sex, or at least these sex-linked traits, girls and women would not have the chance they have now to develop their athletic talents and reap the many benefits of participating and winning in sports and competition. Eric Vilain, a geneticist who specializes in differences of sex development, has been blunt about it: removing sex from the eligibility rules would “be a disaster for women’s sport … a sad end to what feminists have wanted for so long.”


This may sound like hyperbole but it isn’t. In competitive sport, winning and room at the top are what ultimately matter, so relative numbers are irrelevant. It doesn’t matter that there are 100 females and three males in a girls’ race if the three males win spots in the final or on the podium because they are males. The unusually high incidence of intersex athletes in the women’s middle distances and their reported 100 percent win share in the women’s 800 meters at the Olympic Games in Rio show their disproportionate power. Indeed, it is because they clustered in the middle distances that these events are the initial focus of the rules. Their supremacy was proof of principle. Testosterone readings outside of the female range were also found in the throws, but these were attributed to doping, not intersex conditions.

The I.A.A.F. is requiring that affected athletes lower their testosterone levels to within the female range if they want to continue competing in the middle distances in the women’s category. By definition, the required hormone therapy causes medically unnecessary physiological change, and no one should be forced to take drugs they don’t want or need.

But the I.A.A.F.’s requirement isn’t rogue or reckless. It simply adopts the standard of care in transition medicine, which is very much embraced by those who seek to match their bodies to their gender identity. Intersex athletes who have gone through puberty may not want to drop their testosterone levels to female levels if they don’t identify as female or don’t see the need to feminize their bodies for reasons other than sport. This is especially true for athletes who are in the game to win rather than to express themselves through participation as women. This is properly their choice and it’s a real one.

When we’re not focused on intersex athletes we tend to understand the fact of sex differences and their relevance. In the United States those differences are the basis for Title IX and its hugely popular mandate that separate and equal funding be set aside for girls’ and women’s sport. Under Title IX, sex remains the principal and generally uncontroversial basis for classification and legal protections.

Given this, the compromise reflected in the I.A.A.F.’s rules is significant. Using testosterone as a proxy for sex may seem like subterfuge, but it’s not. If it were really sex that mattered and not testosterone, then athletes who had gone through puberty as biological males would be categorically banned from the women’s category as they used to be. Instead, today, if their legal documents identify them as women they can compete as women in the events they prefer if they transition the single sex trait that determines capacity for the win. They can keep their bodies otherwise intact. The process offers fairness both to the affected athletes and to the field.


Doriane Lambelet Coleman competed in track and field internationally during the 1980s and is a professor of law at Duke Law School.

Comments