The age structure of its population affects an economy in two ways. On the one hand the accumulation of human capital, that is education, implies the sacrifice of current labour which size depends on that of the cohorts in education. Further, since ageing affects the abilities to work and acquire new skills the stock of these abilities depends on the age structure of the population. In this paper a representative extended family maximises an intertemporal utility function by allocating the time of its members between (current) labour and schooling (future labour). It is shown that though a lower fertility and consequently a lower proportion of the young leads to higher optimal education, this is not always sufficient to counterbalance the negative effects of the aged labour force on per capita output.