Empirical evidence on three assertions commonly-made by population policy advocates about the relationships among population growth, human capital formation and economic development is discussed and evaluated in the light of economic-biological models of household behavior and of its relevance to population policy. The three assertions are that (a) population growth and human capital investments jointly reflect and respond to changes in the economic environment, (b) larger families directly impede human capital formation, and (c) the inability of couples to control fertility is an important determinant of investment in human capital. The evidence suggests that widely-observed correlations among population growth, human capital and economic variables, which admit to alternative interpretations, are far stronger than are the estimates from studies whose objective is to quantify the causal mechanisms underlying the three assertions; however, there is empirical support for each.