This article offers a theory of economic growth, stagnation, and demo-economic transition that originates from external effects of child-bearing, health expenditure, and education under endogenous mortality. Facing a hierarchy of needs, parents always consume and want to have a family. Child quality, measured as a two-dimensional vector of child health and schooling, becomes only affordable when uncontrollable mortality is sufficiently low. Child quality expenditure initiates an economic take-off and convergence towards perpetual growth while its absence may cause convergence towards an equilibrium of economic stagnation and high fertility. This way, the article provides an explanation for diverging growth rates from a cross-country perspective.