For the one who says it can't happen here - it is happening here.
All of the guidance now given to schools regarding sports says that boys identifying as trans must not be excluded from girls' sports. We also have at least one teenaged male athlete competing against the girls in Scotland (cannot recall where right now).
Most importantly, all trans orgs have lobbied hard to end all single-sex provisions and the government in its response to the trans equality inquiry report says this in Recommendation 13:
We agree that there are likely to be few occasions in sport where exclusions are justified to ensure fair competition or the safety of competitors.
Given that in competitive sports male athletes are always at an advantage against female athletes (apart from extremely rare exceptions thought to be in extreme endurance sports), speaking of "few occasions" is ludicrous or ignorant or indifferent to women's and girl's sports.
There is no mention in Recommendation 13 of the EA, but speaking of justified exclusions is clearly a reference to the EA and it is an insidiuous one at that - because how can a sports club provide the required evidence to justify excluding males? It's been the accepted state of affairs that competitive sports is segregated by sex (and by age), so this evidence hasn't ever been needed before.
So the claim it couldn't happen here and demanding that we should therefore stop worrying about it happening elsewhere has been overtaken by real life events already.