Fertility is a choice by parents involving a life-cycle claim on their resources, from which they
may receive satisfaction as consumers and benefit as producers from children’s labour and care-
giving support. In addition, fertility may be the source of externalities that affect members of
society other than the decision-making parents, in which case society may view fertility as a
legitimate issue for social policy. To forecast fertility and the conditions under which public
policies might be justified to modify fertility, economists require a basic understanding of its
determinants as well as social consequences. In approaching this topic from the perspective of
low-income countries today, the ideas of Malthus remain influential. He argued that population
growth caused by high fertility erodes the welfare and productivity of workers, and thus social
policy which fostered greater fertility, such as the English Poor Law, contributed to
‘overpopulation’. Before considering how these spillover effects of fertility might be identified,
an overview of historical thinking about the demographic-economic system may help to indicate
the context in which Malthus’s thinking was relevant to pre-industrial Europe, and how modern
economics has extended his thinking to fertility as a lifetime choice of parents related to their time
allocation and accumulation of human and physical capital.
Malthus’ framework for the pre-industrial demographic-economic equilibrium
The determinants of fertility have engaged the interest of economists for some time. Adam Smith
(1776) noted families were larger in settings where labour was scarce and child labour was
especially valuable to parents, as in North America with its abundant land. Smith recognized that
child mortality was higher among the poor, especially among those who were dependent on
charity (for example, the Poor Laws). However, Malthus (1798) viewed fertility not as an
individual choice but as an outcome of social institutions, because he did not think birth control
was effective. He thought fertility was governed by the economic requirements society placed on
a couple before allowing them to marry. Once married, the ‘constant passion of the sexes’ would
lead in unregulated fashion to fertility. Society therefore restricted entry into marriage to those
with favourable prospects for a livelihood or the income and assets to support the children that
were expected to follow from the union. Over his lifetime, Malthus accumulated corroborating
evidence on fertility, population growth and economic growth. Historians have since added to
Malthus’s evidence, confirming that Europe exhibited a late median age at marriage for a woman
in her mid-twenties. This delay in childbearing led European women to have four or five births