An idea that's been turning around in my head is a world where the female to male ratio is like 5 to 1, and there are no male only spaces (bathrooms, dorms, locker rooms, saunas, everything is unisex). Every guy is generally going to be surrounded by girls, even when living with roomates.

There's a lot of female chauvinism. And what's more, girls tend to get along really well and don't mind sharing. So they're quick to gang up on guys for a sexual fix or other mutual benefit.