I’m curious how a boy or girl “feels” their sex. I knew I was a boy because I had a penis. It wasn’t that complicated. I didn’t feel like I was a boy. I was a boy.
Where's this kid's father? Or, even, just someone to say "No." and/or explain the facts of life to this poor kid.
Having raised a kid, and been around plenty of them in the process, I can't even imagine this topic coming up. Granted, I live in a conservative small-town, but the conversation, "Dad, I think I'm a binary gender" would uniformly be met with "Nope. You're not." and that would be the end of the conversation. The kid would grow up to be well-adjusted and happy, and life would continue on.