Quentin But I don't think a female sign on a bathroom door ever stopped a male predator from going in and hurting someone. And rape and sexual assault is far more likely to be someone you know than a stranger in a public bathroom.
Anyway, I digress. On the rugby thing, I believe that in youth rugby in New Zealand, kids teams are organised by weight rather than age because they have found that to be much safer (basically the problem was that people of Samoan type heritage get much bigger much younger).
Surely, at a bare minimum, women deserve similar safeguards to prevent them being injured by physically bigger and stronger men?