Does Testosterone Give Female Athletes a "Manly" Edge?
Caster Semenya's 800-meter gold medal in Rio is stirring debate over what it means to be a female athlete
When Caster Semenya took to the 800-meter start line on Saturday, she did it in a uniform that was clearly different from those of her fellow Olympic competitors. She didn't wear cheeky briefs or a sleeveless top. Her green-and-yellow one piece extended from halfway to her knees to halfway to her elbows. Unlike those of the women lined up next to her, her abs were not exposed to the hot Rio air-or to the millions of spectators watching from around the world.
Her body was under enough scrutiny already, with the world questioning if she was really a woman.
It's a question that has chased the 25-year-old South African runner for nearly a decade. Long ago, Semenya got used to competitors accompanying her to the restroom at track meets so that they can verify her femininity, according to a New Yorker article from 2009. That year, she first dominated the World Championships in Berlin with a time that others could only explain by calling her a man. Russia's Mariya Savinova said, "Just look at her." Pierre Weiss, the general secretary of the International Association of Athletics Federations, responded by saying, "She is a woman, but maybe not 100 percent."
The IAAF subjected her to invasive gender verification tests and suspended her from competition for 11 months. Then, in 2011, the IAAF put limits on the amount of testosterone that could naturally circulate within a woman's veins for her to still compete as a woman. Women, like Semenya, who were deemed to be "too mannish" due to high naturally occurring testosterone levels, were given the option: subject yourself to humiliating and potentially fatal measures or don't compete.
These measures included hormone-suppressing drugs or, if testing determined that the woman was intersex, having both an X and Y chromosome and traces of testicular tissue in her abdomen, surgery to remove that tissue. (Related: How Does Transitioning Affect a Transgender Athlete's Sports Performance?)
Since testicular cells in intersexed women are prone to malignancies, it's generally recommended that they be removed anyway, and there aren't currently any FDA-approved medications for the suppression of testosterone levels in women, says board-certified endocrinologist Andrea Dunaif, M.D., director of the Northwestern University Specialized Center of Research on Sex Differences in Chicago. Options exist abroad, but their safety is controversial. Some women take medications intended for men with prostate cancer, she says. Lowered testosterone levels are a side effect. However, so is liver damage.
It's not known for sure what, if any, procedures Semenya underwent, but she was allowed to compete in 2010 and went on to win a silver medal at the 2012 Olympics-behind Savinova, who is currently at risk of losing her Olympic title due to Russia's current doping scandal. (Still, many people were quick to point out that Semenya's times were slowing, a sign that she must have been lowering her testosterone levels.)
In 2015, however, a fellow athlete with "too-high" levels of testosterone, Indian sprinter Dutee Chand, challenged the IAAF's body-altering rules, with the Court of Arbitration for Sport subsequently suspending the regulations. Female athletes with higher-than-average levels of testosterone would be able to compete against other women in Rio without first submitting to medical intervention.
In case you're wondering, Semenya took gold in the 800-meter run on Saturday. With her time of 1:55.28, she earned a personal best, set a new South African national record, and the fifth-fastest time in Olympic history. Hours before the race, the IAAF's president, Sebastian Coe, said that the group will soon try to overturn the Court of Arbitration for Sport's decision and again prevent women from competing with high levels of testosterone.
In a press conference after the race, Semenya responded to questions about her influence on the 800-meter event. "I think it is all about loving one another. It's not about discriminating against people. It is not about looking at how people look, how they speak, how they run, it is not about being muscular. It is all about sport. When you walk out of your apartment you think about performing, you do not think about how your opponent looks. So I think the advice from me to everybody is just to go out there and have fun," she said.
Semenya's fans from around the world have responded with the hashtag #HandsoffCaster, which was a top trending topic on Twitter this weekend, in response to those who have questioned whether she should be competing.
So what does the science say?
High Levels of Testosterone Aren't All That Uncommon in Women
Testosterone is known as the male sex hormone, but women still produce the hormone. The typical adult female has blood serum levels ranging from roughly 30 to 95 nanograms/dl. The typical adult male's levels are around 300 to 1200 ng/dl, explains Janis Fee, M.D., chair of obstetrics and gynecology at St. Joseph's Hospital in Orange County, California.
However, levels in both men and women vary widely-and often.
For instance, on the road to the 2012 Olympics, four female athletes were flagged for high levels of natural testosterone, according to one New York Times report. (It also noted that they had received major treatments including surgeries to reduce the size of their clitorises.)
And a 2014 study from the IAAF Medical and Anti-Doping Department and Commission concluded that seven out of every 1,000 elite female athletes may have above-average testosterone levels. Study authors noted that these rates of hyperandrogenism-medical speak for having higher-than-average levels of androgenic hormones such as testosterone-are far greater than what they would expect in the general population.
Still, the general population is more familiar with hyperandrogenism than it realizes, and perhaps even more so than the IAAF researchers concluded. After all, it's the primary cause of polycystic ovary syndrome (PCOS), of which 15 to 20 percent of women suffer, explains Dunaif. One UCLA study of 716 women with PCOS found that 75 percent were hyperandrogenic.
Hyperandrogenism can occur simply due to genetic differences, but can also be a result of tumors or of being intersexed. But most women with hyperandrogenism don't know they have it, Dunaif says. Think about it: have you ever had your testosterone levels tested?
So Does Testosterone Really Give Female Athletes an Edge?
Most of us know testosterone as something that makes men strong and prevents women from getting "bulky" when they lift weights. And that's true, to an extent.
After all, testosterone is an anabolic hormone, meaning it helps to build cells, like muscle cells, in the body. In men, it's associated with increased muscle size, strength, and bone mass, and with decreased levels of body fat, Dunaif says. And in one Journal of Strength & Conditioning Research study of elite athletes, testosterone levels were correlated with vertical jump performance-a measure of explosive power-in both men and women.
So, while it makes things no less painful for women whose gender identity is publically questioned, it is understandable why it would trouble the competition, Dunlaif says. "I was a competitive athlete. I understand how no one wants anyone else getting an unfair advantage. But these women are not doping or trying to cheat. This is how they were born," she says. "And still, there's no conclusive evidence that naturally high levels of testosterone would enhance exercise performance in women."
What's more, while some experts estimate that excess levels of natural testosterone would give women's performance a boost that would minimize the gap between male and female race times, Dunlaif notes that in women with hyperandrogenism-related PCOS, that doesn't always seem to be the case.
For instance, in one The Journal of Clinical Endocrinology & Metabolism study that matched women with PCOS with women with similar ages and weights, those with PCOS had significantly lower aerobic capacities, anaerobic thresholds, and maximal workload capacity compared to those without the endocrine disorder. A similar study from the University of South Australia found that although women with PCOS had higher levels of testosterone, they displayed no significant differences in aerobic capacity or muscle strength. Fee also notes that PCOS typically is associated with weight gain, not loss.
In the end, researchers just don't have any conclusive evidence to prove whether or not higher-than-average testosterone levels give women an athletic edge. And if so, in what sports.
But does it really matter if they do? "There are so many other kinds of biological variants that can lead to enhanced athletic performance," says Dunlaif, referring to what many experts call "the sports gene."
For instance, Kenyan distance runners have an on-the-track advantage due to the architecture of their Achilles tendons, according to research published in the Scandinavian Journal of Medicine & Science in Sports. Sprinters may have been born with more fast-twitch muscle fibers than were endurance runners, according to exercise physiologists. And elite basketball and volleyball players are a good foot or two taller than gold-medal-winning gymnasts.
Maybe that's just part of sports. We all bring something different to the playing field: ourselves.