Spare the Rod?

Parent who spank their children? Discipline and obedience are key to raising children but I don't believe that one should ever raise their hands on their children. The parents might think its working but they don't know what the child's thoughts are. It may be working for a moment but it could turn out to make their children even worse. The famous buddhist saying about karma is:

"What you unfold to one, may unfold ten times to you?