I think that when we are young we were influenced more by those around us. We mimicked them, their actions, emotions, how to express ourselves. We learned morality. We didn't have the mental capacity at that age to develop our own ideas of right and wrong. For the early years of life we just absorbed and took in the world around. Everything new fascinated us. We were told what's right and what we shouldn't do. Who to be and how to be that person.
I personally think it's impossible to be born bad. How could something so innocent and pure like a baby be bad? There is no supernatural force that determines what we are. All we were was a new life. A new baby. At that age how can your personality be even determined as good and bad? I think we were born neutral. Pure. And then, as time progressed, we were exposed to the energies of people, the love that was shown to us or the love we did not receive, is what shapes us. When we were younger if we had a thought to do something bad, we were taught not to do those things, we learned what was bad. A fear factor stopping us. But we always have a choice. We have the choice to be good, the choice to be bad. We have the choice to follow the bad thoughts. It's the experiences we have throughout life that changes us.
If we aren't shown love, protection and support...how can you grow up good when you don't know what is good? A darkness can grow within you. As a human we have the choice to give in to that darkness or move on, away from it. You have your own free will and thoughts you can;t control but who says you have to act on these thoughts?
So are we born good or bad? I think we are born neutral. Not necessarily something empty, but something that can be influenced and shaped. It's like we are born a blank canvas. We can be something, someone, but we need others to trigger us. The artist can pick up the paintbrush and paint a blue sky or dark clouds. When I was younger I saw the world as God's play mat. He can "play" with whoever he wants, influence their actions but then he can cast them aside. If we are cast aside when we are born who is to say we can't grow up to be bad?
The human brain is a delicate but mysterious trove of knowledge, memories, experiences, emotions and visual images. We have the choices., we can make the choices. This is what shapes us to be either good or bad.