For the subject of the thread, I am convinced there are many ways of being gay. I know people who were straight and turned gay, or were gay and turned straight. A lot of scientists say that it is maybe wrong to divide sexuality in gay, straight and bisexual. There is only one human sexuality, with two poles (the 2 different sex), and most of the people tend to be more or less close to one of the poles, generally the opposite sex. But it can change during life for many many possible reasons.
I don't believe the underlying sexual orientation changes, but rather our recognition & acceptance of it in ourselves. Fortunately many gay men are now coming out at very early ages, essentially concurrent with the development of their sexual maturity in puberty, the same time straight guys "discover" girls.
But it also means that many of them can't understand how men of my generation could have been delayed for so long in coming out, as I was. Well, that's a good development, I'm glad guys are coming out earlier, though sometimes I get annoyed when I get challenged on it by younger guys who didn't live through what we did.
In my case it was caused by the disconnect between my feelings and the gay stereotypes of the 1950s & 60s. I knew from even my pre-teen years that men thrilled me, whereas women did not. But as I began to learn that there were "sissies" who weren't real men, and men who wore women's' clothing and wanted to be like them, spoke with a lisp and minced around, I knew that wasn't describing me.
Therefore, I could not be gay, because I believed that "girly" behavior was essential to the term. If I liked men it must be something else I was feeling, some other reaction, but definitely not gay, or queer, fag or homo.
Being "un-gay" in my behavior (or so I imagined myself, though I was partly wrong on that count, too) was my internal defense mechanism against any thoughts that I might be gay. Added to that was the DESIRE not to be gay, at a time when gay wasn't merely despised by society, but actually criminal & illegal in many parts of the US.
So that I never "turned" gay, I was always gay. What I finally did was recognize it, accept it, and come out to the world. But I was never closeted, which means I knew I was gay but hid it. I didn't hide being gay for so much as a single day once the belated revelation finally came to me.
I also favor the Kinsey scale of sexuality. With straight at one extreme end, gay at the other, bisexual in the center, and an infinite range of possible blends in between. I do think we can drift a little on that scale, I suspect mostly due to fluctuations in our hormone balance, but we don't change our basic orientation. As I said, we can merely change our recognition & acceptance of what we already are, which we and others may perceive as a change of orientation, but really isn't.