I was going to write a post, but turned to google to get help with some phrasing, and found an article already written that encapsulates my thought better than I could have written it. I also think this article dovetails somewhat into StG's line of inquiry about homosexual acts being "off the mark".
Here's the link. This is standard apologetics/logic stuff:
https://www.str.org/w/homosexuality-...ought-fallacy-
I would tighten up his words to say "homosexual sex is unnatural" rather than homosexuality, which would just imply the attractions. I'm consistently trying to make a distinction between the feelings and the acts, the former not being a sin, and the latter being a sin, at least in my grounding of it.
To me, this is like looking at a pile of hex nuts and bolts, and thinking it's totally normal to try to use two hex nuts to assemble a bookshelf. Can you put two hex nuts next to each other? Sure you can. But it's obvious it's "off the mark" of how nuts and bolts were designed to be used in conjunction with each other.
And by the way, this is not an argument related to procreation. I'm just talking about the design for use, not what's produced from the designed use.