I think for younger children it is more about stereotypes. But as they move towards puberty it becomes more about the whole person. Everyone thinks they’re an exception don’t they when they’re younger. ‘It won’t happen to me’. There will be some dysphoric boys who think.. but I really am a girl and it won’t happen to me. My voice won’t break, and I won’t grow facial hair because I’m not going to be a man. Then when those things do start happening it can be devastating. Same for some girls.
But this is magical thinking, and by puberty he should have realised that wishing something to happen doesn't actually make it happen. The adults around these children are failing them by not making it clear to the child that they can't change sex.
And what do you mean by 'more about the whole person'? What is it that is not stereotypes?
I think Datun's suggestion is a good one:
Take a minute and make a list of the ways a male 'can live as a female'. And then read back what you've written.
And post on here anything that isn't about stereotypes or about invading women's privacy (like using women's toilets).