Umm, I'll probably have a hard time explaining myself and it will probably seem like I'm changing my mind throughout this post and any further posts in this thread, but that's 'cause English isn't my first language so keep that in mind, please. 
Basically I think people are born both good and bad - I mean, have you ever met someone who is good all the way? Maybe until you notice that there is something that you don't like about them, when they reveal a bad side of theirs. Same with "bad" people - there is usually something you like about someone who seems bad, if you know them well or if you get to know them.
Plus it depends on what you consider good and bad. Stupid example but racists are considered awful by some and wonderful by others. Maybe it all comes down to opinions...
Edit cause I thought of other stuff:
I think when you are born you aren't neither good nor bad, you're just uneducated. You're too young to comprehend what's good and what's bad, you haven't mad up your opinion about anything.