According to a recent scientific article, a specific variant of the COMT gene can predict whether a child will develop "early-onset antisocial behavior accompanied by attention-deficit/hyperactivity disorder".
I'm not saying that this is the gene variant that leads one to become a sociopath. Yet, I can't help wondering whether the process of evolution intended for some of us to be anti-social. People with anti-social tendencies could be the ones who inspire wars. Since death is the mechanism by which natural selection occurs, having more battles would certainly speed the process of evolution.