Come to think of it all-boys schools probably do have to hire women teachers, since that's an employment situation. If they were all clergy, they might get a pass, but it's the Catholics that have gender segregated clergy, and there have been women teachers in catholic schools for a long time.
Banned under gender discrimination law. All men-only spaces are, except for bathrooms and changing rooms.
Come to think of it all-boys schools probably do have to hire women teachers, since that's an employment situation. If they were all clergy, they might get a pass, but it's the Catholics that have gender segregated clergy, and there have been women teachers in catholic schools for a long time.