This chapter reviews literature connecting genetic differences to political dispositions. We begin with a primer on molecular genetics and functional genomics to contextualize politically relevant genetics within a broad biophilosophical framework. After this primer reviews indispensable complexities and important nuances, an overview of twin studies provides heritability estimates and evidence of additive genetic variance associated with political inclinations. We cite two reviews, and several specific studies, representative of a larger data set yielding moderate to high estimates, broadly indicating that, like personality and other individual differences, sociopolitical attitudes typically show an average heritability of 0.50. More briefly, we consider relevant single nucleotide polymorphisms identified by genome-wide association studies, an emerging approach with potential to corroborate behavioral genetic findings. After cataloguing a representative review of genetic evidence, we thereafter reflect on its significance by: (1) distinguishing between lower-order emotions and higher-order cognitions; (2) considering the lagged expression of genetic effects; (3) discussing models of political ideology to the end of more precisely specifying what is genetic; (4) recounting the way in which states can suppress the expression of traits; and (5) interpreting ideological differences in the context of the Overton Window. These five sections amount to a philosophical reflection on genetic evidence, contemplating what it means when political ideology is said to be heritable.