While I never identified as trans, it was very similar to the level of mental gymnastics and avoidance I went through (and am arguably still going through) to deny that I was gay.

It started with "no, I'm 100% straight and if you dare even SUGGEST otherwise I will get extremely offended", then it progressed to "okay, so maybe I'm a little bit bisexual but I STRONGLY prefer women and wouldn't touch a real guy, ew" - even if that was far from the truth. It then gradually evolved to "well yes, I'm a 50/50 bisexual but I don't date anyone so it doesn't matter", and now it's... acknowledging I'm homosexual in private to myself, though not happily, and simply declining to answer any question or suspicion of my sexuality.

And this isn't even a lifelong thing. What I just described happened over the span of the last three years. And truthfully? I'm still not out of it. I still feel ashamed, I still doubt myself, I still blatantly lie to people and will even sometimes go as far to tell people in real life I have/had a "girlfriend" that never really existed, just so they'll stop asking me and I can dodge the topic.

So, I still can't understand how someone can decide they were really the opposite sex all along, but I can understand how someone can get there. I understand the urge to deny & run away from one's sexuality, and I totally understand the fear, humiliation and shame of being a "failed male" or being the laughing stock of your community because you're not manly enough or "act gay."