Most parents don’t have favorites.
This is a myth!
"Most parents do have favorites, at least in the sense that they feel closer to one child than another due to having more shared interests or understanding one child better than another,” says Sonna.
“Parents often feel closer to the child that is more like them. Alternatively, if parents don’t feel good about themselves, or if they dislike certain aspects of their own personality or of the other parent’s, they may have a harder time feeling closer to the child who displays the disliked characteristic.”