Because you can't trust a college-aged kid (legally adult but developmentally immature) to let their peers (maleor female) feel comfortable about their bodies or to not make them feel like objects. People can get used to it, but I think it's just a lot easier to avoid the confrontation in an already aggressive environment. Dat's what I'm sayin...

It's really a numbers thing.
Some men will look at my penis in the gym shower as opposed to some men plus all the women in the gym shower looking at my penis.

Quite frankly, I don't want anyone looking at my penis in the gym shower, which is why I'm a speed walker.

Remember that co-ed shower scene in Starship Troopers with all the boobs? Yeah. I do.

Dudes don't want to poop around girls.

Girls don't poop. Women's bathrooms are just a cover to go powder and plot together against men. Why would they want that cover blown?

Back in 1985, a college professor told us the story of a Japanese woman who was arrested for using a mens' bathroom; she had no idea that we feel the need to keep these things separate, and felt it said something pretty sad about us. So I guess it comes down to our Puritanical roots.

Barney Frank deserves a "better politicians" tag.

I once used a bathroom in France that had the mens and womens sections separated by teeny saloon doors with the sinks in a common area. I wasn't bothered too much, but my female cousins sure took a long time to finish washing their hands...

(they had a nice view of the urinals)

No, it's because women's bathrooms are absolutely, 100% the most disgusting things on the planet. I spent a year and a half working as a janitor during my senior year of high school and it's like a fucking horror movie in those things.

Request "Barney Frankegory"

sorry Zircon, "better politicians" tickled my funny bone a little more. I'll change it your suggestion if someone links it to a Grayson video, though. :3

Hahah... Cena in the marines.

Frankenstein for Secretary of State.