Not my words but i thought it was interesting
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I think being "gay" is not 1 condition (I mean a metaphysical/existential condition, not a medical one), but several different conditions, whose symptoms/outward signs have the common element of being attracted to the same sex, but whose cause varies. I see it as there being three kinds (which are fundamentally different from each other). (I'll mainly look at male homosexuality)
First, there is a same-sex attraction that is ingrained in the very genes. In this type, there is the campness and men's close affinity to women. It so deep in the psyche, that it almost like women in a man's body. There are certain ticks, such as the swivelling of the head, high pitch voicing and different motor-function to regular males (movement in walk and gait is different).
Second, there is that which is caused be deep psychological traumas at a very young age, up to 3 years of age. In this case, it "psychotic", in the sense, it is a deeply embedded neurosis. This may be caused by stumbling in a room with your parents having sex or an alcoholic parent that distorts and confuses one's very fundamental well-being. In this second case, the person doesn't have the campness of other homosexuals. You wouldn't recognise it, apart from certain signs such as expressions of nausea towards the sexual organs of the opposite sex and of a heightened affinity with the opposite sex.
Third, there is the culturally-induced homosexuality. It is a lifestyle choice driven by circumstances. Some people in prison for example "turn gay" due to lack of female company or others turn gay because they are tired of the way people of the opposite sex treat them. This type may not have a strong a cause as the previous two, but once a person, who goes down the road, there is little coming back, as the fundamental changes to a person's fundamental sense of self and sexual identity would be altered, almost to the degree of the 2nd type.