This article gives a wide-spread overview of the Nature vs Nurture debate in Psychology. The main argument in this debate is whether our personality traits are predetermined genetically (Nature) or that we gain them through personal experience (Nurture). It is a constantly changing debate because there are so many factors that can be argued for both sides. There are so many outside factors that can change any given person, to say that Nature or Nurture is solely responsible is a bit ridiculous in my opinion.
Personally, I believe that a large amount of our persona is formed by Nurture, or personal experience. I don't believe that people are born with their ideologies and beliefs already determined. At a young age, we observe those around us and tend to model those behaviors. As we get older, we begin to recognize what behaviors are good and what ones are bad, what kind of person we want to be, etc.
What side are you on? Nature or Nurture?