The demographico-economic “paradox” suggests that the decline of fertility would be a natural consequence of economic progress. The simultaneity of economic and demographic evolutions raises questions about the causality relation binding population and economic growth. In this research area, the theorists developed models of unified growth highlighting the importance of the parental arbitration between the desired number of children and their “quality” in the transition towards steady-state economic growth. The literature on fertility dynamics remains nevertheless divided between the partisans of the adaptation to rational choices and those in favor of the part played by dissemination of culture and norms. Taken separately one from the other, none of these approaches makes it possible to provide relevant and reliable explanations of the interaction between economic and demographic development. Our research, in extension of these investigations, explores the mechanisms subjacent with the economic and demographic evolutions through the prism of the equality relations between men and women.