There's a parody of the Christmas carol "God Rest Ye Merry Gentlemen" called "The Restroom Door Said Gentlemen". In short, the singer enters the wrong bathroom after some prankster switches the signs, where he finds "two nuns, three old ladies, and a nurse" who turn on him before he's realized what's going on. It's played for laughs, but considering he meant no harm and didn't even begin to do anything threatening, it hardly seems fair that he's hit with a can of mace and a handbag before he even gets half a chance to explain himself. Ending up with "two black eyes and one high heel up [his] behind" feels like something he ought to be pressing charges for. I get that men are expected to stay out of the women's bathroom, and vice versa (though apparently to a lesser extent, given that most people seem to be generally fine with women using the men's room when the women's room is crowded), but that reaction seems a bit excessive. Yet he might have problems even trying to go to the authorities, since the laws in some places are such that he's committed a crime just by walking through that door. That honestly shocked me when I first heard about it. Social disapproval is one thing, but legal prohibition? What a waste of law enforcement.
Which brings me to what led to this posting, though I've been sitting on it for a few months. I was disturbed after seeing an article shared on facebook, about efforts somewhere to promote non-gendered bathrooms—instead of, or in addition to, men's rooms and women's rooms, there would just be generic bathrooms, where people could simply go and dispose of bodily wastes regardless of who they were. Now, it wasn't either this proposal or the article itself that I had a problem with. It was the perplexing amount of hostility in some of the opposition to the notion. I recall, in particular, a vehement assertion that only perverts could possibly approve of such a thing. Well. I suppose that all depends on how you define "pervert".
To start with, there's simply too much diversity in people for any statement like that to be plausible. People can come up so many reasons for so many things that it's difficult to imagine that not a single person has any reasons at all that are even slightly legitimate. Whether these reasons outweigh the opposing reasons or whether there would be a better way to address them or whether they're even logically sound to begin with are all separate questions. It's unfair and intellectually dishonest to simply dismiss these reasons out of hand, much less immediately turn to name-calling. To quote someone who put it rather well, "There are very real reasons why people feel the way they do. ...people with strong opinions about various social matters have those opinions for reasons that, if nothing else, are very real to them, and might even have been borne out of pain." (from author commentary for EGS strip posted 2015-04-27).
Anyway, back to the main point. Single-occupancy bathrooms, as a specific case, have no legitimate reason for gender designation. There's one person in there at a time, so privacy isn't an issue, safety isn't an issue, but-think-of-the-children doesn't come into it... seriously, if anyone can come up with a better reason than "that's just the way we do things", feel free to let me know. (EDIT: I've come across one reason, but I wouldn't call it "better". The law in many jurisdictions requires that facilities be available for both women and men. That's understandable, but the way some of these laws are worded means that a building with three single-occupancy unisex bathrooms, for example, legally counts as having no bathrooms. Which makes no sense, but that happens far too often when the law gets involved.) And taking the signs off ought to help mothers with young sons or fathers with young daughters, at least. In the more general case, if it's such a bad idea to provide non-gendered bathrooms—or, on a related note, to formally sanction transgender people using the bathroom that matches their expressed gender—then surely there are more convincing arguments than calling anyone who might consider allowing it a pervert. I'm having difficulty coming up with any that don't fall apart on examination, though.
Does the question of privacy concern you? Any decent bathroom should provide adequate privacy, and if it doesn't, you should direct your complaints at the designers, not the users. On that note, the same could be argued of dressing rooms and even locker rooms, unless you're trying to say that you don't care who sees you naked as long as they have the same bits between their legs as you do, and that frankly seems silly. Whether strangers can see you naked or not at all, or at least whether they're being abusive about it, should matter more than who those strangers happen to be. Shouldn't it?
Does it concern you that children might seeing things they shouldn't? That gets back to the privacy thing again. It shouldn't be an issue. Besides, if you actually care about your kids, beyond using them as pawns in an argument, maybe you should be keeping an eye them. Beyond that, children are surprisingly resilient, and, more to the point, generally don't care about these things, and probably won't pay any attention to them to begin with, until and unless you make a fuss about them.
Does it concern you that people might abuse their access to perpetrate some improper activity? Anything can happen, but shouldn't people face consequences for what they actually do, not what they might do? Otherwise we're back to the days of trying to ban VCRs (or diskettes, or CDs, or the Internet, or...) because people could use them to make illegal copies of things, instead of focusing on the illegal copying itself (though that's a whole other can of worms). It should be pretty easy to tell when someone is behaving inappropriately (if it's not, then that's again a problem with the bathroom itself), and to respond accordingly. Besides that, it's a possibility no matter who is allowed in. There's no simple way to categorize people so that everyone any given group will be harmless. Ultimately, there's no telling what anyone will do, and what's between their legs is hardly an assurance of innocence. If you take seriously such worries about what other people might do, then you should already be watching your back and wary of strangers to some extent.
Does it concern you because it's against your religion? Well, first there's the question of whether it actually is, and not just a case of your prejudices assuming so and using your religion as an excuse. But either way, try coming back to this one after beef is banned because Hinduism considers the cow sacred, bacon is banned because Muslims don't eat pork, lying is banned because Thou Shalt Not Bear False Witness, and rock and roll is banned because it's the devil's music or whatever that particular bit of hysteria is about. That's not how things work here. If you object to something, feel free to not do it, but that doesn't give you the right to make anyone else follow suit.
Does it concern you that letting someone with a penis and someone with a vagina empty their bladders in different private stalls in the same general space will somehow lead to the downfall of society, or something similarly ominous? How? I've seen hysterical claims that similarly innocuous things are causing the downfall of America, but really, now. Maybe you should think that one through a little more.
Does it concern you that people who don't conform to the customary either/or male/female gender binary would be able to deal with a basic biological necessity in a civilized manner, while having a legal recourse in case of harassment or worse, instead of having to worry about potentially being arrested for simply going about their business? Yeah, it's definitely time to rethink your priorities.
And if you think it's acceptable to enforce restroom segregation by checking people's genitalia, then I think it's time to consider rethinking who's really acting like a pervert.