If homosexuality is innate/genetic, how has it survived evolutionary selection, given that a homosexual couple produces no offspring?  Wouldn’t an evolution-based standpoint argue that homosexuality is developmental?

Evolution … it’s not what I’m guessing you think it is.

The theory of evolution doesn’t argue that traits have to result in offspring. It simply posits that traits that contribute to survival tend to get passed along to offspring. As far as I know or anyone else knows, survival traits aren’t limited by sexual orientation. Furthermore, a lot of traits that don’t contribute to survival also get passed along, so take that for what it’s worth.

The current thinking is that 3% to 10% of any population is QUILTBAG. And sexualities exist on a spectrum, not always 100% one way or another for a great many people. This is further complicated by people’s personal preferences (tall, short, large, thin, curvy, muscular, funny, serious, kinky, vanilla, monogamous, non-monogamous, “switchable,” etc., etc.). There’s just as much preference variation within QUILTBAG populations as there is outside of them.

I’m a straight cisgender man. According to the theory of evolution (at least on a macro scale), I should be doing everything in my power to have babies.  And yet (on my own personal micro scale) I have never, ever, even by accident, behaved in a way that would get someone pregnant. This is because I don’t want to be a parent. I don’t want children and I don’t think I ever will. My personal preferences override any genetic “urge” I’ve ever had. Conversely, there are plenty of QUILTBAG individuals that would feel incomplete if they didn’t have and/or raise children. Go figure.

There will always be a percentage of people that aren’t straight. Whether it “develops” or whether it’s inborn is less important than people’s orientations, preferences, and gender identities being respected whatever form they take.*

* Assumes ethical behavior and consent without coercion/force.