The route through childhood is shaped by many forces, and it differs for each of us. Our biological inheritance, the temperament with which we are born, the care we receive, our family relationships, the place where we grow up, the schools we attend, the culture in which we participate, and the historical period in which we live—all these affect the paths we take through childhood and condition the remainder of our lives.
–Robert H. Wozniak
Nurture vs. Nature is the biggest and most enduring issue in psychology. It is the debate that asks the question: are we who we are because were born that way, or do our experiences shape us? It looks into different genes compared to the environment that we were raised in. Most psychologists can come to the conclusion that in fact, both do influence us, but many have an opinion as to which has a greater influence. Personally, I have always thought that nurture was of greater importance.
There have been several different cases and experiments where nurture vs. nature has come into play. The best case studies with nurture vs. nature are feral children, since creating a feral child is a "forbidden experiment" because of various ethical reasons. These studies on feral children, while rare, give great information about the nurture vs. nature debate. Studies done more often for nurture vs. nature are twin studies, since they are quite a bit more practical than feral children studies. Since (identical) twins have the same DNA, they are easy to compare on the nature side. Twins separated at birth that meet each other later in life are great for nurture vs. nature. In the video above, twins were separated at birth when they were adopted as part of an experiment. When the experiment fell apart and the twins finally met each other through the help of the adoption agency, they couldn't help but notice the similarities in their personalities. One twin even goes on to say "I think nature trumps nurture". And they should know, they are a living nurture vs. nature experiment.
I don't know that the nurture vs. nature debate will ever declare a winner. I just think that everybody has their own theories as to which is more prevalent to a person's development. As for me, I still say that nurture beats out nature for the most part. I'll demonstrate it with a picture: