Diversity of Fertility Levels and Implications for the Future

Human fertility has never been so varied. In some countries the average number of births per woman is close to one, only half the level required for long term stability of population size. In other countries the average woman is having six to seven births. The possible reasons for this diversity and the consequences are discussed. The problems of excessively high fertility are probably more easily solved than those of very low fertility. Much experience has been gained over the past 40 years in how to reduce childbearing, mainly by high quality family planning programs with accompanying publicity to legitimize the idea of small families and use of modern contraception. Conversely, successful experience at raising fertility is much less common and the future of very low fertility countries remains uncertain. The paper concludes that fertility in the range of 1.7 to 2.3 births, implying modest long term decline or increase in population is probably optimal.