I know a guy that is a textbook definition of a sociopath but there's no indication of anyone like him in his family. He is a fifth generation Mormon from a very good family. (I'm not trying to convince anyone that Mormons are any better than any other group or religion, but although they may be annoying there are not many I've heard of that are considered evil.) But religion aside, there is no record of anyone like him on either side of his family for generations. As far as I know none of his relatives have a criminal record, yet he is a total maniac.
He's been busted for many drug crimes, violent crimes, theft, burglary and forgery, and those are just a fraction of the crimes he has actually committed. He has done so many unspeakably bad things to his family that most of them are completely numb to his sociopathic criminality. He gets away with a lot of his crimes by being a police snitch. He would stab anyone he knows in the back to keep his freedom, including flat out lying about them (he is a pathological liar).
He started hanging out in a very bad crowd as a young teenager. So bad that his entire family packed up and left California and moved to "Mormonville" just to get him away from it. He immediately found the worst crowd in the area and picked up right where he left off. His parents are incredible people with a great reputation and he had a great childhood. What can make someone like him just snap and become evil? It can't be genetic in his case can it?
For over twenty years he has continued to steal everything in sight, deal drugs, terrorize people, lie to destroy people's reputations, abandon his children, sleep with every crack whore in town and make his family absolutely miserable. His last two engagements (as well as some other relationships) ended with a restraining order against him. His parents and children are embarrassed of him. He can lie and weasel his way out of almost every situation with his silver tongue. Now that he is a police snitch he has a virtual get out of jail (trouble) free card and uses it to it's full advantage. How is someone like that created?