Funnily, in trans men/women, their brains biologically are more similar to their gender identity than to their assigned-at-birth sex.

Similar =/=. And it's not even that similar, there are recorded many people who have the same similarities without any delusions about reality.

How can you be so sure of the future? We can 3d print other organs, why not a functioning uterus or set of testes, in the future when we figure that out?

You wanna print every XY into XX yes? Not possible, nor will ever be possible without killing you and genetically engineering a new human.

No, my sexual relations are me looking to cum. You can argue that that biological drive is doing that, but I take every precaution to not have kids. Like, to the point where I pull out while wearing a condom. I don't want those damn crying poop machines at this point in my life. So don't generalize.

As I said, pleasure is the incentive not the purpose.

and yet you say that gender isn't a social construct...

Are you capable of reading? I never said anything like that. I said that gender is irrelevant, because a woman isn't a gender, it's your sex. A woman is a human female.

And? If you went out, had sex with a MtF transexual, post-op, and you couldn't see anything wrong with her, how would that be any different from having sex with a woman if you never knew that she used to be a guy?

So tricking a man into believing you are a female via operations/hormones/drugs and cosmetics because his brain never had the need to suspect that something that looks like a female isn't actually a female, that something that looks like a woman isn't actually a woman, that is moral yes? That is your morality? He didn't USED TO be a guy, he still IS a guy. That doesn't change. He is just a guy that made himself to look like a woman. That doesn't make him into a woman.