We show that in an open-economy OLG model, the interaction between growth differentials and household credit constraints—more severe in fast-growing countries—can explain three prominent global trends: a divergence in private saving rates between advanced and emerging economies,large net capital outflows from the latter, and

This paper analyzes the impact of relaxing fertility controls and expanding social security in China. We develop an overlapping generations model in which fertility decisions and capital accumulation are endogenously determined in the presence of social security. In our model, children are an alternative savings technology—as they transfer resources to their retired parents. Important feedback links arise between fertility and social security variables: an expansion of social security benefits reduces fertility—partially offsetting the effects of relaxing the one-child policy.