Study: Male Athletes Transitioning to Female Retain Massive Strength Advantage Despite Hormone Therapy

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A study published in Sports Medicine found that testosterone blockers taken by biological men who want to live as women do not significantly diminish their strength and gives them an advantage when competing against biological women in sports.

The study found that elite male athletes are around 10 to 13 percent faster than female athletes and the difference in sports like bowling cricket balls, hitting long drives, and weightlifting is even greater — 29 percent to 52 percent.

“Performance differences larger than 20 percent are generally present when considering sports and activities that involve extensive upper body contributions,” the study said. “The gap between fastest recorded tennis serve is 20 percent, while the gaps between fastest recorded baseball pitches and field hockey drag flicks exceed 50 percent.”

The Guardian reported on the study:

When transgender women suppress testosterone for 12 months, researchers found that the loss of lean body mass, muscle area and strength was only around 5 percent. Therefore, they say, “the muscular advantage enjoyed by transgender women is only minimally reduced when testosterone is suppressed” and “small compared to the baseline differences”.

The results are significant because under the current International Olympic Committee guidelines, transgender women are allowed to compete in female sports categories if they suppress their testosterone below 10 nmol/L for 12 months before and during competition. Yet even when testosterone was suppressed to around 1 nmol/L it did not “remove the anthropometric and muscle mass/strength advantage in any significant way” – although the authors say the reduced cardiovascular performance may generate smaller retained advantage in endurance sports.

The study raises significant questions for sport, with the paper stating “the IOC may need to reassess” whether its current guidelines for transgender women are fair or safe for female competition. They also ask whether, from a medical-ethical standpoint, it is acceptable for the IOC to ask trans women to significantly reduce their testosterone if it does not deliver on its stated aims.

In fact, researchers found that the biological gap between men and women is so large that the “10,000 males have personal-best times that are faster than the current Olympic 100m female champion, as does the 14-year-old male schoolboy 100m record holder.”

“These data overwhelmingly confirm that testosterone-driven puberty, as the driving force of the development of male secondary sex characteristics, underpins sporting advantages that are so large no female could reasonably hope to succeed without sex segregation in most sporting competitions.”

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