I could trace family disputes and misunderstandings to so many factors but one hidden and obscure factor lies in the hands of most parents. I grew up to understand the teachings of Esau and Jacob in the Bible, how the mother loved the latter more than the former. Not only did she love Jacob secretly, it was made open till it escalated to conniving against the other son. This was made possible because the father as well, loved Esau more than Jacob.
Funnily enough, many people have adopted this lifestyle traceable to what happened decades ago but they've forgotten that Christ was made to come just so some policies could be abolished. My heart quirks when I hear a parent say he or she loves a particular child more than the other in this era. For the mere fact that you've made it clear that you don't really like one of your children, chances are that the child will do whatever he pleases because he knows there's nothing he'll do to please the parent. In extreme cases, it creates room for enmity amongst the siblings.
No child is totally bad, no child is totally good, most times it depends on how they're treated. Just like adults, we're bound to make mistakes but we try to reshape ourselves to become useful in our family and society, same goes with a child. It's the duty of the parents and older people to caution a child(with prayers inclusive) on how he should live and lead in the family and not outrightly telling him that you prefer his siblings to him. Most parents do these with the aim of correcting the child or make him behave like others but it turns out to be the opposite because you've psychologically delineated the child.
Every child has his own gift and nature, we only need to understand them and pray his or her gift doesn't bring reproach to the family. Like Christ said, love is the greatest of all and He loves everyone irrespective of certain factors.