I'm not sure about the cinema seat thing, but I would say that homophobia seems to be much more prevalent among guys. When I was in high school, I would sleep in the same bed as my girl friends without thinking about it twice, but even in university (where supposedly people are more mature) guys seem to be afraid of any kind of contact with another male. I don't think it's a personal space bubble thing, because they sure like cuddling up to girls, but two of my roommates won't even sit on the same couch together if there's another chair free.