Ofcourse being gay is at least part environmental.
I asked a friend 20 years ago on South Beach why he was Gay. He said he didn´t know if he was or not, he was just experimenting.

I remember not understanding. I have experimented with a lot in my life, but I could never experiment with being with a Man.

It was definitely cool to be Gay on South Beach back then. Tons of Gay clubs, Gay´s everywhere. They were sharply dressed, in good shape, had money, and had more fun than the average straight guy. At least that´s how it appeared.
I was an entrepreneur back the as now, and remember discussing targeting the Gay community, where the money is.

As I got to know more people, I found more men being drawn to the Gay lifestyle, and living as Gay without being "Biological Gay".