What is the concept of "original sin"?

How can any parent gaze upon their newborn child and believe that the child is sinful and deserving of their gods wrath? When my children were born, I saw them as completely innocent, harmless beings that I loved and would protect against ANYTHING! Even some Imagined GOD. If anyone asked me to hurt my child I would oppose them in any way possible. If some being asked me to take my child and murder him as outlined in the bible I would immediatly say no! you evil prick, I will defy your wishes for me to murder my child because it is wrong. I love my child and any harm that comes to him comes from you, not me you evil, evil tyrant that would even ask that of me!