Numerous studies indicated that the prevalence of certain alleles of the dopamine D2 receptor gene (DRD2) vary across different ethnic groups. Under adverse environmental conditions, these alleles can increase the risk of developing psychiatric symptoms. Thus, we hypothesized that the prevalence of the DRD2 gene Taq IA allele may serve to explain the horrific behaviours practiced by the Nazi regime. Hitler's 'Brain Washing' methods goaded his followers to carry out genocide at a time when carriers of the DRD2 TaqIA allele (the so called 'aggressive--genotype') were significantly higher among the Aryan Germans compared to resident German Jews. It would be of interest, to genotype the Jewish Holocaust survivors, to determine whether those with the Taq AI allele survived in greater numbers. The hypothesis being that, greater survival may result in enhanced frequency of not only the DRD2 AI allele but other reward gene polymorphisms among survivors. Understanding the molecular genetics of any population in terms of reward dependence and subsequent behaviours will be most beneficial in future human interaction whether negative (war) or positive (peace) in nature.