Cohort birth order, parity progression ratio and parity dstribution trends in developed countries

Tomas Frejka, Independent consultant
Jean-Paul Sardon, Institut National d'Études Démographiques (INED)

This investigation is part of a project analyzing childbearing trends and prospects in 35 advanced countries using the cohort method. The principal finding of the project: Childbearing was the lowest ever early in the 21st century and is not likely to increase in the foreseeable future. The present research aims to analyze in detail trends of birth orders, parity progression ratios and parity distributions to further the understanding of the mechanisms generating contemporary low fertility. A general decline of first, second and third order births was under way among the 1960s cohorts; births were being postponed. This birth postponement was continuing among young women of the late 1960s and 1970s cohorts. Usually only fractions of delayed births were being recuperated later in life. The “two-child family” which was most prevalent in the 1950s cohorts was declining across the board; proportions of childless and one-parity women were on the rise.