To support this conclusion, Bongaarts points to a puzzling discrepancy between expressed preferences for family size and measured fertility in most low-fertility societies. If women in a given country have the same number of children in their lifetime, but later in their lives than their predecessors, this will appear to be a reduction in annual birth statistics. Once women stop deferring births, the distortion disappears and the very low fertility rates observed in the developed world should rise closer to the 2 children most couples want. For example, in France the annual total fertility rate has been reported to be well below the replacement level since the mid-1970s. But in actuality, French women who have reached the end of their childbearing years report having 2.1 births on average, close to the preferred number.
Similar discrepancies exist in many other developed countries.
In the United States, fertility rose from 1.77 to 2.08 births per woman between 1975 and 1990 as the postponement of births stopped. It is therefore plausible to assume that fertility in Europe and Japan will not decline further and might even turn upward soon. Different policies Policy implications for both conditions sizable population growth in developing countries and below-replacement levels in developed countries call for different approaches, Bongaarts says. Indifference is not one of them. This effort should be strengthened and expanded to include social investments in young people for example, girls' education that help offset population momentum and improve the quality of individual lives.