The brain sends out instructions BASED ON THE INFO PROVIDED BY THE BODY. So ultimately, it's your DNA that tells you what sex you are (also how many body parts). The fact that the message is conveyed through the brain and can get garbled if the brain is not functioning properly should not be overlooked.
Not sure I understood the questionable grammar of "most of all human beings, is the same", but I can tell you that there are rather significant differences between males and females. I can also tell you that you are undermining your own argument by saying there aren't, when YOU are the one insisting on "male brains" and "female brains" being these big, immutable objective standards which trump all other concerns, such as biology. If there's no real difference (and every time you say something like this, I feel an overwhelming surge of pity for virtually everything about your life and experiences, if you really believe that), then why the **** are these transgender people making such a big to-do?
I can only shake my head in disbelief at the idea that you really think the only difference between men and women is what type of underwear each has.