While it’s perfectly valid to ponder, question, and discuss .. I doubt there are any universal answers. Personal answers may be approached through such introspective work as you hint at in your writing, and of course by various forms of “therapy” (which may or may not be actually therapeutic) and perhaps most powerfully in dream-work, deep contemplation, or spirit-medicine work.

I was severely physically abused by step-dad from age 7–13, and sexually abused probably a couple dozen times at age 13.

I guess I was “born straight” — though I was continually derided as “a faggot” in elementary school thru the beginning of junior year of high school (when I miraculously became immensely popular at a new school as a cutting-edge member of the stoners group — this was the mid-sixties.)

I have had great friendships with boys/men and girls/women, and your post got me to think about abuse vs. sexual orientation .. my conclusion (in my case only) is that if I had been attracted to a male in sexually-tinged manner, I probably would have experienced a lot of internal conflict, which would’ve raised the childhood abuse into a very present emotional dissonance.

I’ve had queer friends in the past, more recently was a member of the “Cafe Gratitude” family in San Francisco, which was dominated by queer women, and also a fair number of gay men .. I had good working relationships with almost all of them (a couple of divas whom I prob’ly failed to properly worship excepted) and a loving emotional energy with many.

I guess the “take home” from my sharing this comment might be
sexual orientation — as well as many other factors in our lives
is all so very unique and personal — that I have a hard time recognizing sole or even partial “causality.” 
- with love :)