The Onset of Fertility Transition

Abstract

For many years it has been known that in virtually no human population has the level of fertility ever approached the potential biological maximum. Scholars have long been aware that such factors as constraints on marriage, prolonged breastfeeding, periods of separation or abstinence, abortion, and disease have exerted a restraining influence on fertility. Thus while systematic investigation of the relationships determining fertility levels had to await the work of researchers such as Kingsley Davis and Judith Blake, and John Bongaarts, ' the seeds of two basic ideas-first that the prevailing level of fertility is the outcome of a balance of factors, and second that even in a high-fertility population birth rates could possibly risehave long been germinating. Confronted with the beginnings of widespread rapid population growth in developing countries during the 1930s and 1940s, demographers such as Kingsley Davis, Warren Thompson, Frank Lorimer, and Frank Notestein naturally initially identified the cause of faster growth as improvements in mortality. Although they recognized the two aforementioned ideas, in those early days there was no evidence to suggest that there had been any rise in fertility, whereas there were good reasons for thinking that death rates had declined.2 Moreover, the view that rapid population growth resulted from mortality decline in the presence of high and more or less stable birth rates was consistent with the main descriptive and theoretical statements contained in the early writings on demographic transition theory, of which these scholars were key formulators. In the 1960s, however, there emerged a significant qualification to earlier views. While improvements in mortality were still seen as the primary cause of the acceleration in growth, several writers now maintained that the role of