Dar-Nimrod and Heine (2011) presented a masterfully broad review of the implications of genetic essentialism for understandings of human diversity. This commentary clarifies the reasons that essentialist thinking has problematic social consequences and links genetic forms of essentialism to those invoking neural essences. The mounting evidence that these forms of essentialist thinking contribute to the stigma of mental disorder is reviewed. Genetic and neuroessentialisms influence media portrayals of scientific research and distort how they are interpreted by laypeople. The common thread of these essentialisms is their tendency to deepen social divisions and promote forms of social segregation.