It's true, some parents have a favorite child and they will tell you outright. In fact, I've read that most parents do have a favorite child. I guess I am always a little shocked since I never felt that I loved or cared for one of my 5 children more or less than the other. Sure, if a child was sick or dealing with an issue, I always tried to make sure they got the help and attention they needed. Maybe it's because I have a tendency to see good in all people, especially my children. And perhaps I have a bonder stronger than most with all of my children, who range 10 years from youngest to oldest.
It definitely can be a hardship for a child who was the favored one when they are not treated as such in the real world. And children who observe another of their siblings being treated as special are known to have issues of low self-esteem. If a parent does have feelings that they prefer one child over the other, then it would be best to not show these feelings in front of the other children. Sure, we all have a somewhat different relationship with each of our children because they all have their own personalities and talents.
If you do have a favorite child, how do you deal with this issue?