There really is no logic to it and it goes against the natural order that was established by our creator. The bible clearly highlights the role of parents in their children's lives.
For example in Proverbs 1:8 it states: "Listen, my son, to the discipline of your father, And do not forsake the instruction of your mother."
Ephesians 6:4 states: "And fathers, do not be irritating your children, but go on bringing them up in the discipline and admonition of Jehovah."
So then clearly we can see that besides the natural bond that a child shares with their parents, parents are commanded by God to take care of their own and raise him in their ways. The question is how do all these different beliefs and ideas come about? Visit www.jw.org to find out