A Trans could be a "Male brain" inside a female body. Or a "Female Brain" inside a male body. Men and women have different brains. There is no superior brain, but there are key differences. And each brain is not only different, but effected by hormones differently. That's why a Female Trans says that they feel like a "woman trapped in a man body". Because they technically are. Or vice versa.

They are a (let's just go with) female brain in a male body, they grow up their whole life knowing something is... Off. Because there is. Their female brain requires Estrogen the female hormone. But it is receving testosterone. So they know something is not right because they not only meantally and emotionally feel it, but physically also. This would air on the side of birth defect because they were born in the wrong body and seek to change it. Just like with most birth defects. (It's not supposed to be an insult saying birth defect. Just a fact. They are born one gender, when they were supposed to be another. That is a defect)

Then you have the actual mental disorder. A person that claims to be a car, just because they stand in the garage. Just because they stand in the garage that does not mean they are a car. That person would be a little crazy, wouldn't you say? Saying you are a woman but doing nothing to change or try to make yourself into a woman is just as crazy. Identifying as a woman no more makes you a woman, than simply standing in a garage makes you a car.

Now, if they get surgery, do hormone therapy, wear makeup, act like the gender they are trying to become. Then those people are at least trying. They may be onto something. But they should get a brain scan, not see if they are crazy, but rather to prove that they physically are a man/woman trapped in the wrong body