Parental investment represents expenditures of time and resources for the purpose of increasing the biological fitness of one’s offspring. We examine whether parental investment has incidental effects on per capita GDP, using a cross-section of 209 countries and territories. Our work is a revisiting of a 2002 paper by Nigel Barber, with some notable methodological improvements: we use a spatial lag model to control for Galton’s problem, use multiple imputation to handle the issue of missing data, and consider the implications of endogeneity. Our results show that variations in parental investment explain nearly half of the variation in per capita GDP. We find the role of health investments to be especially critical: increases in offspring health raise the rate of return to parental investment, which prompts even more investment, creating a deviation-amplifying process.