The battle over trans athletes in American schools heats up

ESMEE SILVERMAN feels unusually nervous about the prospect of trying out for her high-school girls’ tennis team this autumn. That is not surprising: last year, she played for the boys’ team. For the past ten months the 18-year-old has been taking a combination of oestrogen and testosterone blockers as she transitions to becoming a woman. “It’s a big emotional shift going from one team to another,” she says, adding that she expects it to be made easier by the kindness she has been shown by girls her age.

Ms Silverman is fortunate to live in Massachusetts, where transgender students can play sports as the gender with which they identify. Policies on this vary from state to state. While more than a dozen have introduced guidelines like those in Massachusetts, which also allow trans students to shower and change with members of their chosen gender, 11 states have policies that prevent this. Some say birth certificates are the final arbiters of sex; others, that transgender students must first have had gender reassignment surgery (which is generally restricted to over-18-year-olds). As an increasing number of teenagers reject the sex they are born with, these clashing approaches are sparking court cases.

In Idaho, the American Civil Liberties Union is battling a statewide law that bans transgender women and girls from female...