We compare Alfred Marshall, Vilfredo Pareto, and Knut Wicksell on the relation of family size to poverty, considering their (1) views on Thomas Robert Malthus, (2) contributions to statistical studies of population and standards of living, and (3) theories of poverty. While they shared the conclusion that to reduce poverty required decreasing the family sizes of the poor and working classes, they diverged on how this should be accomplished. Marshall rejected the use of contraceptives and argued that family limitation should arise from delayed marriage and restraint within marriage. Pareto thought such recommendations unscientific and unrealistic. Statistically, it was clear that people practiced preventative checks to varying degrees across countries and across classes; privately, Pareto supported the use of birth control as a responsible choice. Wicksell took the most radical position, publicly advocating for legal contraceptives and sex education for everyone regardless of class or marital status. We show how their working out of the problem of poverty subsumed additional questions of positive and normative science and the role and status of moral judgment in policy. Their discussion of the public interest in private reproductive choices reflects many of the same tensions that characterize contemporary discussions, indicating the continuing relevancy of the topic.