This article takes a look into the nature versus nurture debate through presenting information from various studies. According to the info presented in this article I believe that it is a combination of the two, being nature and nurture, that make up a person.
Many things about us are determined before we are even born. The color of your eyes, the shape of your face, and the body type you will have and live with during your lifetime. These characteristics, however, are generally physical and easier to trace back to their parent. Scientists debating the nature hypothesis want to take things to a different level and insist that traits such as intelligence, aggression, personality, and even sexual orientation are determinable by someone's genetic makeup.
While difficult to quantify, according to this article studies have shown that fraternal twins show great characteristic similarities when raised apart from each other. From this discovery, we can deduce that, without similar genes, when raised apart these fraternal twins would be completely different. This would also mean that when raised together, they develop nearly identical characteristics. This study was also done in trials using identical twins, establishing the idea that genetically similar individuals develop closely related traits regardless of their environment.
Scientists supporting the nurture hypothesis suggest otherwise, stating that these genetic similarities can produce similar traits but the environment of an organism's upbringing can change those traits. One such study, recorded in New Scientist, showed that humor is a trait learned from one's environment (family, culture, religion, etc) and is not necessarily determined by genes.
Similar to the nature hypothesis, the nurture hypothesis is not easily quantified either. However, we can look at studies done with identical twins. According to genetics these individuals are exactly the same and, when raised apart, they should develop exactly the same characteristics. Studies show otherwise, that genes can have influential power over what you are but your environment ultimately determines who you become.
Overall, in my opinion it must be a combination of the two. For example, consider the genetic makeup of a great athlete. Tall, muscular body type, fast metabolism, all of which are determined by genetics. However, now consider an environment that is not conducive to athleticism. Junk food, exercise not promoted by the family, etc. If this person were to not exercise and eat poorly they would never have the ability to use their superior genes to excel in athletics. On the other hand, someone who does not have these genes who grows up in a similar household won't be able to excel in athletics either. The difference there is that they never had a chance, because they didn't have the genetic makeup to do so. This shows that it must be a combination of the two, nature and nurture, that make a person who they are.
The following video shows a study of the nature hypothesis being conducted using two identical twins.