Because there used to be a saying that newborn children should sleep on their heads, that is, they should sleep flat on the back of their heads, so that wearing a hat would look better. People don't think like this anymore. And there is a saying that the bigger the brain, the smarter the child is. Therefore, for the sake of children's intelligence, parents nowadays generally don't give their children a hairstyle. Naturally, the back of the head is sharper than before, which is normal.