Abstract:The present investigation aims to provide a general modelling framework for the dynamical implication of age structure for macroeconomic growth. First we build a general dynamic framework embedding the age structure of the population in descriptive macro-economic growth models in a fully realistic manner. We do this by considering on the one hand a generic model of descriptive macro-economic growth, defined by a set of n ordinary differential equations, and on the other hand the fundamental equation of age structured population dynamics, i.e. the Von Foerster partial differential equation, and proceed to integrate them by suitably modelling the main link function between the economic sub-sytem and the demographic one, that is the rate of change of the labour supply. Compared to other works in the literature our approach is fully general, in that we can consider age-dependencies in essentially all feed-back parameters reflecting how inputs from the economic system affect demographic behaviour. Second, we look at the main static and dynamic implications of fully taking into account the age structure of the population for macroeconomic growth. We study the existence of equilibria. We provide conditions for the existence of joint balanced-growth paths of the economy and the population, i.e. paths of balanced growth of the economic sub-system allowed by the balanced growth of the population. Finally we report a conjecture suggesting that age structure appears to be the major source of demo-economic oscillations.