Mothers with young children present may have them with them in the locker room. But if their child goes without them to the male bathroom and something happens, said child and mother should be believed when they report that event.

A lot of it depends on context, really. A passing post-op transwoman enjoying a sex-segregated spa should be allowed to access that spa if permitted. Penis should stay in the penis zone. But things like rape relief services should be allowed to disqualify you for admittance if they deem that appropiate.

All minors should be allowed to have predatory adults removed. But that does not permit male minors to access women's spaces automatically.