The nature versus nurture argument is an important issue in the social sciences. It basically asks whether human beings come by the traits that they have through inheritance (nature) or through being taught those traits (nurture). This is a perennial issue in the social sciences because it is very difficult to differentiate between the impacts of our genes and the impacts of our upbringings.
For example, this debate is particularly prominent when it comes to intelligence. It often appears that intelligence runs in families. If parents are intelligent, their children usually are intelligent as well. Siblings typically have at least somewhat similar levels of intelligence. The problem is that it is hard to determine how much of this similarity comes from genes and how much of it from upbringing. Intelligent parents tend to do things like reading more to their children and bringing them to places like museums that stimulate their intellects. When their children turn out to be intelligent, is it because of their genes or their upbringing?
We also see this debate in things like sex roles. Women and men tend to play different roles and have different attitudes. Is this because they are naturally different or is it because society teaches them to be different.
Thus, the nature versus nurture argument is an argument about the roles of genetics and socialization.