Is homosexuality genetic or learned?

Someone at Apologetics Academy asked "Is homosexuality genetic or learned?". My response:

1. So a more technical answer is it's multifactorial and polygenic. At the same time, the same could be said for any sexuality (e.g. heterosexuality, bisexuality).

2. Moreover, sexuality (in the way it's used in the post) isn't limited to physical properties alone. There are also significant psychological elements in sexuality. It's the distinction between biological male/female (which is physical and physiological) vs. what does it mean to be masculine/feminine (which is more psychological), even though the one can influence the other.

3. In fact, homosexuals and transgendered persons debate this. Many people aren't aware, but there's an internecine battle waged within the LGBTQ umbrella. In general, homosexuals want to argue biological sex is fixed, whereas sexuality is fluid. (I think I use "sexuality" differently from the way it's used in the post.) So one is a biological male since our genes are fixed, but sexual orientation, behavior, attraction, and so on are e fluid (e.g. butch, femme, dyke, boi, stud, top/bottom).

By contrast, in general, transgendered persons want to argue biological sex is fluid, while sexuality is (usually) fixed. So, for example, a biological man can have sex reassignment surgery and become a biological woman. This would mean biological sex is fluid. However, though they are now a (transgendered) woman, they will argue they continue to have sexual desires for women, hence they are akin to lesbians.

This, of course, angers the homosexual community in general. Such as lesbians. Lesbians don't wish to have sexual relations with a transgendered woman who used to be a man but now believes they are akin to a lesbian.

4. Finally, it depends on one's underlying worldview. If one is an atheist materialist (naturalism), then they might argue we can reduce everything to the physical. That presumably includes psychological properties being reducible to physical properties. Like how the mind is reducible to the brain.