Union instability – how does it affect fertility? – the case of Sweden

In Sweden, as in many other countries, the patterns of partnership formation and dissolution has changed substantially with a general trend towards less stable unions. This study aims to give insight about the development of childbearing caused by union instability. Stepfamily fertility is studied for the period 1970–2011. It is measured by studying how many children who at birth have half-siblings, and by studying how many women and men have children with more than one partner. The analysis is based on register data containing information on childbearing histories of all women and men in Sweden. The results show that the impact of stepfamily fertility has declined in the 2000s. In a logistic regression model the reasons for this decline is explored. The results of the regression models show that factors such as postponement of family formation, higher educational levels and increasing numbers of foreign born only partly can explain the downturn. Thus, there are also other explanations. One could be increasing gender equality.