The fight over trans kids in sports isn't really about genitals — it's about testosterone, and whether one year of hormone therapy is enough to make competition fair.

On the basic science, research supports the idea that testosterone gives men a physical edge: studies of anabolic steroids show they build strength and muscle, though that doesn't automatically translate into better sports performance, and research on trans women on hormone therapy found their strength and muscle shrink but stay above typical women's levels for years. The harder question is whether a single year of testosterone reduction is enough to make competition fair, and here the research genuinely splits. One study followed a single trans cyclist whose lab numbers moved toward female ranges after a year, hinting it might be enough — but that's one athlete, far too thin to prove it works in general. Other research found that after a year most of the male advantage is still there, and a separate study found roughly a quarter of trans women on hormone therapy still had testosterone above common sports limits at one year, though it didn't actually measure whether fairness was achieved. Worth noting: none of this research was linked in the post.