The fight for the future of transgender athletes – The Washington Post

The first was published in 2004 by Louis Gooren, a Dutch endocrinologist and founder of the Center of Expertise on Gender Dysphoria in Amsterdam, one of the largest transgender health clinics in the world. “Testosterone exposure has profound effects on muscle mass and strength,” wrote Gooren, who reported that as he gave more testosterone to 19 transgender men, they saw marked increases in muscle growth, as well as hemoglobin and insulinlike growth factor levels, both relevant in athletic performance. As he suppressed testosterone in 17 transgender women, the opposite occurred: Their muscles shrank, and their hemoglobin and IGF levels dropped.