This dissertation explores issues of efficient and inefficient population in complete and incomplete market economies with altruistic parents who cares about the welfare of their children. Altruistic models with idiosyncratic risks are central to modern macroeconomics, particularly when studying issues of inequality and redistribution. But this framework seems to fall apart when serious consideration is given to fertility decisions as Barro and Becker (1989) because some of the most appealing conclusions obtained under the exogenous fertility assumption are seriously altered. For example, optimal fertility choice tends to eliminate intergenerational persistence of inequality. A main goal of this dissertation is to recover key features of demographic facts using micro-founded macroeconomic theory and quantitative approaches, and to derive normative analysis regarding efficiency of population, long run inequality, education, and demographic policies. The consensus of my research is that family decisions made by altruistic parents have substantial aggregate socioeconomic consequences in dynamic environments.