When you are growing up during childhood, there are certain stages you go through psychologically. There's like an oral stage, an anal stage, an a couple others I can't remember cause its 1 and I've had a long day..... Anyways, what a psychologist would consider a normal adult someone who went through all of those stages. Someone who is gay may have had something wrong (different to be PC) during the anal stage (just an example). Someone who tends to bite their fingernails, chew on pencils, touch their mouth when their nervous could have had something go 'wrong' during the oral stage. That's my best explanation right now. Someone please correct me if I'm wrong or elaborate on what I said.