Well, maybe I just don't have a lot of close female friends any more, but the female friends I do have are literally labeled in my brain as 'people' before 'female'. Unless the whole 'love at first sight' phenomenon occurs; I might appreciate the aesthetic beauty of a woman as far as me knowing my surroundings but rarely will sexual feelings- ever get involved in the social contexts I am in when hanging around the female friends I do have.
So maybe I'm just looking at this question from a somewhat... inexperienced/rusty point of view? Because I do believe cross-gender friendships are wholly possible, when both parties are in understanding that they are both 'human' before a certain gender.
Than again when relationships are forged, barriers are broken- and knowing a person well makes the cannon ball into a bomb-shell. At first the skirmishes of chaotic feelings with rapport, before a possible full blown war of emotion occurs.
In hindsight, I might be thinking in circles. Ahhh-well.