Okay-
No I am not a professor, not hardly, I wouldn't like to give any false impressions.

Homosexuality-
Mostly i just lump it in with all the forms of eroticism.

Eros is one of the styles of sexual expression, the others being mate selection, reproduction and dependence. All are motivated by the sexual drive, which as we know originates with the reproduction of DNA. Now there's a long story, mitossis, meosiss, chromosomal recombination, etc., etc..
On the other hand, it would seem also to be heavily influenced by mate selection, wouldn't it?

Well, i have a little bit of buisness to get to.
Inclusion-exclusion. This is a principle I use to explain a lot of behaviors, both individual and group, or social, behaviors.
But it starts small, it is almost possible to describe the essential action of the cell wall as inclusion-exclusion. Containing, including, desired material and excluding undesired material, almost but not exactly. You need a microscope to see it.
It is almost possible to describe the process of speciation as inclusion-exclusion. You need a macro-scope to see it.
Behavioraly speaking, inc/ex predominates the socializing process, or should I say, the process of socialization?
It is also significant in the process of personality development.
What I'm going to do is let that stew, then I'll get back to you.

A lot of this stuff has to work its way in gradually, it did for me, certainly. I'll tell you a tale, I have this particular text on psychology that details the basic Freudian interpretation circa 1965, I picked it up at a thrift store for fifty cents some years ago and read it. (Personality and Development, a dynamic approach, wish i could give you the author but I don't have it here.) I looked at it again last year, i hadn't touched it since the last time i moved, a decade ago. (Wow, that's a suprise.) And in there, on a blank page, I had scribbled the basics of "Socialization is competitive sexual selection & dependence is a drive, the primary expression by the infant elicits the secondary expression by the parent." Now how did that get there? I wondered. I was certain that i had had the revelation (insight) at a totally different time and place, years later. It took it that long to percolate back up.
So what I'll do is bumble mumble around and refresh this thread or maybe the other from time to time until I think the time is right. Okay? Maybe I'll drop in on some of the other threads as well but don't expect much, I'm not good at advice, especially not at taking it.
But! If anybody wants to jump in on this discussion I'm game, just remember, I can only get online when the library is open.