Population and education are likely to play a central role in public policy in South Africa as it emerges from years of apartheid. Using household survey data, collected as part of the Project for Statistics on Living Standards and Development, the paper examines some of the mechanisms that underlie the negative association between fertility and education. First, education is not randomly assigned within a population. By placing the spotlight on educational attainment around natural exit points in the education system, it is demonstrated that part, but not all, of the association between education and fertility does reflect self-selection in educational attainment. A naive interpretation of the effect as entirely causal would be misleading. Second, education and household resources tend to be correlated and so a woman's education may simply be a proxy for her, or her family's income. This turns out not to be the entire story in South Africa: after controlling for spousal characteristics, household income, labor market choices and even community characteristics, female education continues to have a powerful negative association with fertility. The third set of experiments attempts to isolate the relationship between skills that are likely to be learnt in school and demographic outcomes. After controlling for income and education, performance on a set of quantitative and comprehension tests has an independent impact on fertility. The impact of comprehension skills is particularly large in magnitude, suggesting that the acquisition and assimilation of information may be important in affecting family decision-making.