This dissertation contains three different essays, each of them adding conceptually and empirically to the existing literature on mortality and fertility. The first essay explores the role of chronic conditions onto the US educational differences on mortality. It proposes a model to decompose the influence of any given health state on the socioeconomic gradient in mortality, where the components are the incidence rate of chronic conditions, the mortality of individuals with chronic conditions and the mortality of individuals without chronic conditions. Empirically, the study shows that incidence and excess mortality associated with chronic conditions are equally important with regard to the socioeconomic gradient in mortality. The second essay shows that variations in the risk of HIV infection are associated with lower investments in children. This study focuses on data from rural Malawi and shows that conceptually, higher risk of death may be associated with lower investments in both quantity and quality of children. Empirically, this study measures child health and education at the same time, and uses an innovative follow-up database of children in rural Malawi to show that higher risk of HIV leads to subsequent lower fertility rates and lower investment in the health and education of both girls and boys, and to. The third essay introduces a quantitative index of fertility recuperation. This study proposes a summary measure of the fertility rate after the first birth and shows that this rate plus the mean age at first child can be used to decompose the cohort's completed fertility. Empirically, it shows that recuperation appears both in recent and older cohorts, and that, when observed, the size of recuperation is substantially high.