I never really understood them, but if a couple is ok with having one, then I don't see a problem as long as it doesn't interfere with relationships within the family. I guess I feel like the decor around the house should be a mix of both styles of the couple, so there would be no need for a space for only men. Women want to have a place to get away too, so it would make more sense to me if it was a place for anyone to relax if need be.