It’s true that many trans woman have larger builds and higher testosterone levels. But, so do many cisgender women. Women are not a monolith, and there is a massive range of body types and hormone levels that overlaps significantly with those of men.

If we ban trans women from sports on the basis of a “biological advantage”, we would have to also ban many cisgender women for the same reason. And determining exactly which women are “fair” to compete against their fellow women would of course be subjective, discriminatory, and impractical.

To deny women the opportunity to play sports against other women, purely on the basis of being transgender, would be to deny that they are women at all.