I do mean person born a male that wants to become female. Anti-trans people often make points that trans people are just forced into being trans by the trans-mafia (or whatever term they use) aka social pressure. A brain scan indicating a female brain would counter that. But as I said, they'd probably find other excuses "it's a mental disease that can be treated" and so on and so forth.
I was saying it would be less interesting if it scanned say a female-to-male trans person and returned a result of female (correctly guessing the sex but not the gender), than if it had returned a result of male (that is correctly guessing the gender but not the sex).
That would embolden the anti-trans crowd.
Science is ongoing though, so who knows what the results will be.
The more data you have, the more confident you can be that the resulting categorisation is correct. If you're saying this is incorrect, I disagree with you. If you're saying absolute confidence that the categories themselves are correct is impossible, then I agree with you