Favoritism always has difficult side effects. (anger, rejection, bitterness,feelings of not measuring up. etc) It is God's will that we love our children equally and bring them up in the training and admonition of the Lord. Each child needs unconditional love. Never say, "I wish you were like your brother, sibling..." One may be more compliant and the other more difficult, but never is there an excuse to love one more than the other. Having said that, we are not perfect parents. When one child is more difficult than the other, we sometime find ourselves in that very position, sometimes struggling for right perspective.) It is the time to confess that attitude and seek God's guidance. (My husband says that we are only as happy as our most unhappy child. Just a thought.)