Do Transgender Athletes Have an Unfair Advantage?
When I’m referring to transgender athletes, I’m specifically referring to those who transitioned from male to female.
Before we get to answer the question, we need to understand what ‘tolerable’ fairness is . Sport is not fair.
Those with better genetics, greater access to high-level training, and the financial support to compete at the highest level have a much greater chance of making it to the elite level of sport. The odds are stacked against those with less opportunity.
Those athletes that are taller have a greater advantage in sports such as the high jump compared to shorter athletes, while short-limbed athletes may perform better in sports such as Weightlifting. Further, females with higher natural testosterone levels still compete against other females even though they have an advantage.
These examples would describe what we as a society allow as ‘tolerable’ fairness.
Logically, if athletes can possess these physical or hormonal advantages, then transgender athletes competing in female sports should also fall under a ‘tolerable’ fairness. However, there are some distinguishing factors that would suggest otherwise.
- The IOC guidelines for testosterone limits in transgender athletes is 10 nmol/L, 9x the average female levels .
- Female athletes can’t take exogenous testosterone to reach these levels.
- Transgender athletes maintain their pubertal male adaptations even when transitioning to females.
To further assess whether transgender athletes have an unfair advantage, we must investigate how transitioning from male to female affects performance.
The IOC guidelines of transgender athletes having testosterone levels of 10 nmol/L for 12 months prior to competition in order to “minimize any advantage in women’s competition” and to “guarantee fair competition” .
The IAAF has further reduced this to 5 nmol/L in order to “ensure a level playing field for athletes” . However, reducing testosterone levels in transgender females doesn’t seem to revert all of the male adaptations derived from puberty.
It has been shown that even after 24 months of testosterone suppression, transgender women maintain bone mass . Bone mass may even be preserved over 12 years which suggests that sporting advantage from increased bone mass would be retained.
No study has reported muscle loss greater than 12% with testosterone suppression, even studies that tested transgender male to females after 3 years of therapy . After 12 months of testosterone suppression, muscle loss is only around 3-5% on average.
Considering males have approximately 40% greater muscle mass than females, this reduction still leaves transgender athletes with a great advantage.
Similarly, a reduction in handgrip strength of 7% and 9% after 12 and 24 months respectively has been found in transgender women .
Further, when transgender women had testosterone within a normal female range, a decrease of only 4% in grip strength was found after 12 months of hormone therapy.
This lead to transgender women being in the top 10% of female grip strength scores. Further, transgender women remained 50% stronger than females after 12 months of testosterone suppression in the lower body .
Even 3 years after sex reassignment surgery and 8 years of hormone treatment, transgender women have been found to still be in the top 10% of females regarding lean body mass and have a 25% stronger grip .
These data suggest that strength, lean mass, and skeletal structure are maintained to a higher degree than the average female even in the long term for transgender women giving them a strength advantage.
Unfortunately, no controlled research has investigated the effect of testosterone suppression on endurance performance.