Warbler said:

but then we'd have to get rid of the urinals, wouldn't we? I mean would it really be appropriate for a man to stand at a urinal, do his business, while females could be walking around the bathroom?

You've never been on a metal festival, haven't you?

Here at a local festival at some point the aiting line on the women's restroom is quite.. bad, while on the men's room ist is more or les short. So oftne there are women just using the men's room. And:

No one cares. Guys standing at the urinals just ignore the women, while they just ignore the guys at the urinal.

On the other hand, a guy never enter the women's restroom there. (well I would say because the waiting line is longer, but I thing men won't do it, if it would be otherwise.

Sexism isn't just a men problem.

Some femisists are just going to extreme in the other side. In a perfect non sexist world, there won't be any need of gender specificated toilet, even if I really have to say, I really enjoy the silence on a men's restroom, no talking, just.. well.. not allways such silent.

The best way would be some kind of the bathroom system:

Men, women and "I just don't care whom I am sitting next to"-toilet.

Some people just feel more easy on a gender specificated restroom.