A child stating he is superman doesn't make him superman if you use the proper perspective. I recall my grandson watching a cartoon and he was idolizing the bad man for his strength.
I told him that the bad man never wins in the end and although he was strong the hero was stronger and smarter enough to win.
If my son had told me that he was a girl I would have pointed out to him that he was born who he was 'a boy' and that if he would learn to use his imagination he would have many adventures that girls could not. I lost so many tools when my 5 sons were growing up I had to start buying the cheap ones because they never came back home and I think there are so many forts and treehouses around in the woods that they could have housed the whole community.
I played into everything they needed to grow up to being men. People would phone me and 'tell on' my sons and I would say 'wow, I'm glad there are having fun'.
It was only going up the beach a ways and camping for the weekend but they came home occasionally for food, water and lighting material for their campfires. They were old enough and wise enough by the age of 12 was the oldest one. They in total were about 12 friends who stuck together like glue and had a ball. They are all very nice young men with families today.
Appropriate answers to fit the occasion just dial heaven.