Aggression is nature and nurture. Someone who has no history of aggression in their family could end up having a bad case of it if they were never taught properly by their parents how to deal with their emotions, or were not taught how to behave. But, it is also nature because some people really do develop these issues from genetic pass downs.
All of human behavior, like all biological creatures, can be shown to have a basis in nature. Nurture places a role, but it is not the origins or source of such behavior, nurture can only mitigate or encourage already existing biological tendencies that can probably only be gotten rid of with genetic engineering of some sort.
My home environment whilst young was very safe, however, when I met friends who were very violent and aggressive I felt to be accepted I needed to conform to this group for acceptance. We went through stages all of which included anti-social behaviour, crime and the genaral statement whereby the notion of 'boys are boys' was acceptable. I firmly believe that friends and attitudes of peers and our environment adds to aggression