Thread by @Telegraph

Woman lifting weights Male levels of testosterone during puberty, which are around 20-30 times that of female levels, help increase muscle mass, decrease fat mass, increase bone strength and height, and improve haemoglobin concentration

Read more: telegraph.co.uk/health-fitness…

🏋️‍♀️ Last week it was announced New Zealand’s Laurel Hubbard will become the first transgender athlete to compete at an Olympic Games.

@hoovlet, who earned her PhD at Harvard studying sex differences and testosterone, explains the facts

🧵👇

⚖️ Is it fair?

“I won’t comment on whether it’s fair, but I can comment on whether trans women, who have experienced male puberty, would have an advantage, on average, in most sports over natal females: yes they do”

📉 Are there biological advantages?

"Reducing testosterone levels after puberty, as is the case in male-to-female transgender people who suppress their testosterone levels as part of hormone therapy [as Hubbard has], does not eliminate these advantages"

Athletes transitioning from male to female must:

📌 Declare their gender as female for at least four years
📌 Demonstrate their testosterone levels are below 10 nanomoles for a minimum of 12 months
📌 Maintain those levels throughout the duration of their eligibility to compete

💪Power of puberty

Hooven says the advantage has already been gained.

Male levels of testosterone during puberty, which are 20-30 times that of female levels, help increase muscle mass, decrease fat mass, increase bone strength and height, and improve haemoglobin concentration

“Depending on the sport men outperform women by 10 to 50%. For weightlifting in particular, the male advantage is about 30% – not surprising, since males have, on average, about 30 to 40% more muscle mass than females”

🤝 Ethics and the law

“A fair solution to this complex scientific and ethical issue should be decided through open discussion and debate, in light of facts, and with sensitivity for the concerns of all parties, and without shaming those who hold views different from one’s own"

🏳️‍🌈 Gender wars

“I felt a lot of anxiety [in writing her book on testosterone] because it’s obviously controversial, but I’m somebody who doesn’t like a bully, and I like science, so I felt emboldened to stand up for what I believe in"

🧪 Social justice v science

"Social justice issues are getting twisted into the science, and it’s driven by fundamental misunderstandings...If you hang your agendas on certain scientific facts, you’re going to be in trouble if those facts turn out not to support your agenda"

📚 Risk of backlash

“I don’t use the ‘accepted’ language. I refuse to say ‘sex assigned at birth’, ‘cisgender’, not even ‘gender identity.' So for those reasons I do expect backlash. But I hope it’s a resource, for trans people, gay people, everybody. To learn about themselves"

Read the full article here 👇

telegraph.co.uk/health-fitness…