I haven't read this whole thread, just the question that started it. I think I feel that any crush is just on what one sees or feels at that time, in those circumstances. For instance, I tend to think gymnast Nastia Liukin (link below) is very attractive. However, I do not know her as a person, obviously, so my "crush" might be destroyed if I were to hang out with her for, like a week. That said, I have had crushes on older women, but it has tended to be ones tha have youthful features, such as author Sarah Vowell (I especially love her speaking voice, something that reels me in every time). And, for reasons maybe unknown, I think that "teacher crush" that you talk about is definitely legitimate, but it is only based on the "cool teacher" persona that the child has regular access to.