You're not born a great boxer, its something you learn.

I think its very niave to expect much out of the kids of famous boxers. Obviously there are some huge exceptions (PBF, Cory Spinks, ect). But think about it. Roberto Duran was dirt poor, and started training boxing early, working his a** off to provide for himself and his family. He came from nothing so he had ambition, he was hungry, he had drive. His kids aren't growing up that way, because of Roberto's success and wealth they don't have the same life experiences of conditions that their father had, conditions and experiences that probably made him the fighter he is.