Would say at least generally, that our parents or those acting as such (even if not blood related) played a role in whatever we came to identify with be it sexually or otherwise. We are the product of those who raise us. In some instances the influence is higher than in others depending on the issue, and which ever parent was the dominant influence.
In my case, my Mom divorced Dad when I was 10 and was a very strong-willed working parent. Catching me and my cousin fooling around often she made mention once that starting out sex so young would have me experimenting with gay sex because girls will have bored me. Such a strange thing to say it burned its way into my long-term memory.

And sure enough, in my early 20s I did try sex with guys. Whether as a direct result of Mom's prophetic warning or other things I can't say. But I would say her attitude about sex influenced my own. She's very sex-positive at least with heterosexuality and I grew up with access to her various sex manuals ("Joy of Sex" et al.) They were my first sex education as well as masturbation material (this was well before the internet took off.)
We have a close open relationship to this day and while my openess about things sometimes results in her getting embarassed like asking if she owned a good vibrator and if not would she like one for her birthday, in all we have a great relationship. And I credit her with who I am.
"I'd rather be hated for who I am, than loved for who I pretended to be." - Me.