There have been studies on the behavior of new borns and young children and the results were that they are kind, helpful and understanding. They learn the concepts of greed, suspicion, mistrust, xenophobia and aggression, they don't inherit them. It was a multi part BBC feature on human behavior, I believe. Suspicion develops when you made bad experiences. These experiences are caused by abusive behavior of older people, the social environment. It's a vicious learning cycle, but it's not human nature.
Deks has a point.