Do you actually realise what you are saying? I'm really not sure that you do. But it's an example of the muddled thinking that replaces any logical understanding of the problem.
What you have just said is that any man can pretend to be a woman, dress up and put make-up on to gain entry to a women's restroom to sexually assault women. Well, yeah, that is a possibility if a guy was dumb enough and desperate enough and was prepared to break all the existing laws that we have against that.
So you think we need another law against it? Apparently it worries you, so I guess you do think that existing laws aren't enough. It seems that you need someone on the door to make sure that whoever enters isn't someone pretending to be a woman. But no, hang on. Let's be sensible about this. I think we could both agree that it would be a remarkably stupid thing to do, checking every woman to make sure that she wasn't a man intent on sexually assaulting women.
But that's exactly what you say concerns you. Despite there being zero evidence for it.