This paper gives an overview of the current debate in the cognitive theories of religion over the relative role of social and cultural versus biological and cognitive factors in the development and formation of religious beliefs. One of the key elements of this debate is the so-called Born Believers thesis. Here we identify and analyze in detail its underlying assumptions, major components, and argumentation. We also show limitations and weak empirical validity of the alternative to Born Believers thesis hypothesis — treating religion as the result solely of religious socialization and enculturation. Furthermore, we identify the place of the Born Believers thesis in the context of the wider “innateness” debate in cognitive sciences. This thesis satisfies the minimum condition of “innateness” and may serve as a useful heuristic tool in cross-cultural research and in studies of children’s religiosity. At the same time, we demonstrate how the Born Believers thesis reveals the limitations of the cognitive approach to the study of religion in solving the problem of “innateness” of religious beliefs.