Nature vs. Nurture
One of the oldest arguments in the history of psychology is the Nature vs Nurture debate. Each of these sides have good points that it's really hard to decide whether a person's development is predisposed in his DNA, or a majority of it is influenced by this life experiences and his environment. As of now, we know that both nature and nurture play important roles in human development, but we have not known yet whether we are developed majorly because of nature or due to nurture.
Here are some links that may help you with your research:
Nature vs. Nurture - use login: laconiahs pw: sachems
The Secret World of Siblings - use login: laconiahs pw: sachems
Mean Genes - use login: laconiahs pw: sachems