Echoes of those debates ripple outward from pools to weight lifting rooms and tracks, to cycling courses and rugby pitches, and to the Olympics, where officials face a fateful decision on how wide to open the door to transgender women. Sebastian Coe, the Olympic champion runner and head of World Athletics, which governs international track, speaks of biological difference as inescapable. “Gender,” he said recently, “cannot trump biology.” The American Civil Liberties Union offers a counterpoint. “It’s not a women’s sport if it doesn’t include ALL women athletes,” the group tweeted. “Lia Thomas belongs on the Penn swimming and diving team.” The rancor stifles dialogue. At meets, Ms. Thomas has been met by stony silence and muffled boos. College female athletes who speak of frustration and competitive disadvantage are labeled by some trans activists as transphobes and bigots, and are reluctant to talk for fear of being attacked. Dr Lucia Schroeter Gmail com