First and foremost, this idea presupposes that there is one way to be “female” or “male”, one way to teach those things, one way to experience, them, etc. That is obviously inaccurate, if for no other reason that the obvious one that gender is not a real thing, therefore, it lacks any consistency in its definition, presentation, or realization.
Secondly, saying someone was “socialized as [whatever]” and that affects who they are now is a tried & true tactic of transphobes the world over. While I recognize that most people who are not transphobic and use this concept do not mean it in a harmful way, it is pretty harmful to use an idea that is kind of the core of all modern transphobia.
Third, following up on the above, this concept is kind of an under the radar way of saying someone is not “100%” their chosen gender. As in, “He’s a man, but he’s really a woman”, or “She’s a woman, but she’s really a man”. Trans & gender variant/non-conforming people are not “part something else”, unless of course they identify that way, but even then, it doesn’t make them any less anything else.
Lastly, humans aren’t finite in who they are. Each and every one of us changes and grows and moves and expands as life inspires us to, and as a result, someone can be something for the first 18 years of their life, and then something else for the next 60. In fact, I would expect most people to “grow out”of their childhood, and in the case of a life-changing & life-affirming thing like transition, I would hope the person becomes someone new. I would hope that something that huge would have a profound enough effect on them that they put themselves together in a new way.
It’s not that I don’t believe we treat children differently based on a variety of factors, including gender, and that that treatment affects people down the line. That’s obviously true and real. I’m living proof, if nothing else. But it’s not possible that something that happened to someone in their youth sticks with them in an irreversible way. And it’s not particularly fair or kind to treat people like they can’t change, no matter what they do.
So, in conclusion, please reconsider using this concept and/or phrase when you are describing either your experience, or the experiences of others.