Union Formation and Marriage Formation in Times of Fertility Decline: The Case of Sweden in the 21st Century

Sweden has experienced a decade-long period of falling birth rates. Analyses of Swedish register data reveal that the decline was confined to first births of women and men in co-residential unions, but that the fertility decline was otherwise strikingly similar across socio-demographic groups. At the same time, rates of marriage formation have also declined. In the current study, we take a deeper look into patterns in union formation in Sweden during the 2010s and their relation to the decline in first-birth rates. We show that the propensities to form cohabiting unions did not decline, and that the declines in marriage formation and the propensity to become a parent hold independently of each other. We conclude that cohabiting women and men refrain from elevating their union status to a more committed level, as manifested by marriage or parenthood. These trends cannot be linked to any structural changes occurring in Sweden, such as those related to the business cycle or changes in social policies. In our concluding discussion, we discuss our findings including the more recent trend changes in union formation that occurred during the Covid-19 pandemic in 2020-21.