Your culture and upbringing made you what you are. If you had been treated like a girl you may not have been the same person that you are.
Absolutely.
My point is that culture and upbringing cannot be separated from sex and gender identification.
Well, sex it can, that's a biological determination, but gender I'd agree is a function of society and culture.
There is no such thing as a boy or girl being 'left free to choose'.
Choose between what?
Everyone needs to be taught and trained to be what they are, without which suitable neural connections will not happen.
They're people, and they need to be taught that. They are unique, individual people, and whilst some of them can be grouped by, say, their reproductive organs, that no more needs to primarily define or limit them than, say, their physical build or their height. These all have formative influences on them, there are necessary, unavoidable restrictions that these physical realities impose, but we don't need to culturally add to impositions and expectations.
The personality will not develop without culture and training.
It can't develop without cultural influence, certainly, but how are we training people to be something when we have no idea who they're going to be when they get there?
O.