It's different though. When a white couple gives birth to a child, it can be male or female. I believe that this somehow gets confused, and then the body is one and the mind is the other. However, this can't happen with race, not if both the parents are white. There aren't any other races involved in the gene pool to create this confusion.
There are like 1000 studies on trans people that show it is a real thing.
Rachel Dolezal is pretty much the only 'transracial' person anybody has heard of and it was clear she did it for attention/to be a victim (she made up a hate crime against her).
I feel like most of the people who say 'if transgender is a real thing why isn't transracial!11!' are the same people who think trans women are just men deceiving people.
First of all, it has to be considered that I think only white people are able to do 'this'. Please tell me if a black person woke up one day and suddenly said, 'I've felt white my entire life' people would call them coon, white-washed, self-hating etc.
No. Race and gender are both social constructs, but race is strictly defined by your skin color in greater society. For example, a black woman can't put on skin lightening cream and a pair of Uggs and expect everyone to treat her as if she's white. Rachel Dolezal got away with it because black features are easier for a white person to appropriate than vice versa.
When a person born in a man's body wants to become a woman, they are giving up all of their male privilege. They are also giving up their cis privilege. When a gay/lgbt person comes out, they are giving up their straight privilege and all of the societal perks of being straight.
If a white person claims to be trans-black, they don't actually give anything up. Sure, some people will think they are "weird" or "just joking," but they'll still always have those societal perks associated with being white. If they wanted to, they could easily dissociate themselves from the rest of the race, and live again as a white person. But for gays (as an example), there's no such thing as going back in the closet, lol.
So this is why I don't think transracial will become a thing.
No. Men and women have different brains, which is why being transgender is a thing. People of different races don't have different brains. Race is skin deep.