There are many disorders that cannot be explained or seen, how can you be so sure that transgender people are not suffering from a hidden malfunction at birth of being born with the mismatched reproductive organs and chromosomes?
I get where you're coming from and for what it's worth I'm not closed to the idea that medical science will discover some biological basis for trans identities in the future. And for what it's worth i don't think trans people are lying about what they feel or experience, whether or not they're dysphoric I'm happy to believe that they're all reporting their feelings honestly. I believe that they are experiencing something real, and I understand that they believe those feelings represent a "gender identity" and a knowledge of what it's like to be the opposite sex. I believe Christians as well when they tell me that they experience a soul and a personal relationship with God. Maybe one day medical science will find a basis for those feelings as well. But until that day comes I have to take reality as I find it. There is no science to support the idea that a gender identity exists, just like there's no science to support the existence of a soul. And even if there was it wouldn't prove that transwomen literally are women just like a soul wouldn't prove a God exists. So until then, while I support everyone's right to believe whatever they want to believe I don't want either gender beliefs or religion influencing legislation, dictating medical and social policy, or being taught as fact in schools. Not believing in an innate gender doesn't mean I'm denying trans people exist or are lying any more than being an atheist means I'm denying Christians exist. I believe them on the "what", I just think they're wrong about the "why".
I think people found it hard to understand the whole ‘Adam and Steve’ concept when they themselves did not feel it
The difference here for me is that I do experience a sexuality. I understand feeling attracted to the opposite sex so it's no leap to understand feeling attracted to the same sex. But I don't experience a "gender identity" - I have no sense of woman-ness beyond an observation of my biology. I say I have a female body because that's the label given to the phenotype I have, and I call myself a woman because it's a synonym for AHF. Everything else is just my personality, there is no "intrinsic woman-ness" to any of my thoughts, feelings, or interests. They've been shaped to a degree by my socialisation, which I received on the basis of my biology, but they aren't innate. It's less like a homosexual person explaining their sexuality to a heterosexual person, and more like them trying to explain it to an asexual person. But even in that case it's pretty easy to explain. Given that a "gender identity" is something supposedly every person has, and we are all aware of it to the degree that we can tell if it matches our biological sex, and it's so important that it's the ultimate measure of reality over biological sex, I don't think it's a huge ask that just one person should be able to give some kind of coherent explanation for what it actually means. Ironically the most coherent description I've heard so far is Suzie Green's "being a cis woman means you're like Princess barbie" Jelly Baby thing. That makes sense to me. The down side is that if that's the case I've never ever met a "cis gendered woman" and I doubt I ever will. So if the big POMO revelation is just that not all women like pink - yeh, congrats to them, most of us already figured that out.
I think there was a study recently that said trans brains align more closely to that of their desired sex.
I've read a lot of these "lady brain" studies and what they actually show is that certain elements of transwomen's brains (not the entire brain) align more closely with that of the brains of women in the control group than that of the men in the control group, but that over all those elements of the brains of men and transwomen were more similar to each other than either were to women's brains. All the studies I've read suffered the same methodological problems of small sample size (tens of people) and didn't take confounders into account (most notably sexuality). It's also worth noting that our brains are so plastic that even study participants who spent a week at a mindfullness course had brain differences detected afterwards which distinguished them from the control group, so it's hardly surprising that transwomen would have a few minor brain differences. If there's a compelling study out there though I'd love to see it.
I find it interesting that people are so sure of themselves that man=man and there’s nothing else too it?
I don't claim absolute certainty over anything. But at the end of the day, even if they come up with some new medical discovery that lets us create a definition of "woman" that includes transwomen and women but excludes transmen and men, it won't change the underlying problem. Transwomen will still be bigger, stronger, have penises, and be physical indistinguishable from men therefore giving them a male socialisation and making it impossible to determine who is and isn't a threat. They'll still outstrip women in sports and be a danger in prisons. The science behind it, whilst interesting, would have very little practical application.