I think people need to avoid the “when it starts happening in large numbers” idea. This has already affected hundreds of women and girls.
When two athletes were allowed to compete in Connecticut high school athletics, Selina Soule and every other girl whose place was lowered by one or two in every competition these athletes took part were disadvantaged. Same with CeCe Telfer.
Aussie rules has 18 players on each side. When Hannah Mouncey was allowed to play in the lower leagues, one of Mouncey’s teammates sat on the bench each game. Maybe another didn’t make the squad because their place on the bench was taken. All of Mouncey’s teammates were disadvantaged by having to share changing facilities. All of Mouncey’s opponents were disadvantaged by having to tackle Mouncey. Then multiply that by how many teams are in that league. Then add the umpires who were placed in a compromising legal position should any serious injury had happened to a woman. This is hundreds of women.
When Mouncey switched to handball, a woman didn’t get selected to represent Australia at the world championships because Mouncey was in the squad. A woman who made the squad didn’t get to start in the final. All of these women were disadvantaged by having to share facilities with Mouncey, something they complained about.
When McKinnon won at the Masters cycling championships, every woman below had their place moved down by one.
When Laurel Hubbard won weightlifting gold in Samoa, Feagaiga Stowers, an 18 year old indigenous Samoan woman, a survivor of abuse, was denied gold at her home games. Every other woman who finished below Hubbard had their place lowered by one.
And so on, and so on. Hundreds of women and girls affected negatively already by just five examples of transgender athletes. It doesn’t need to get any bigger, it’s already too big.