When a child enters this world do they even know what good and bad are? I don't think this is possible. They learn what is good behaviour and what is acceptable because they are praised for doing certain things that their parents perceive as good. I believe that goodness and badness are brought about by life experiences.
You may argue that many scientific experiments suggest that X% of people are born good but I myself believe that it is the world we live in that decides whether each and every one of us turns out good or bad. The people we are surrounded by form our opinions on life, love and everything else that goes along with that! Certain experiences that every person goes through at some stage of their lives mould you into the person you will eventually turn out to be. Losing someone, to death or otherwise, fights with family and friends and many other things all contribute to the whole person you end up being. No child is born with experience and therefore cannot form opinions on anything in life.
''We are born innocent, totally ignorant and in a state of complete dependence.''
CM