The Role of Sex Differences in Re-partnering for Sex Differences in Post-separation Fertility by Age 48: A Cohort Perspective

Abstract

Individuals increasingly transition through more than one cohabiting relationship during their reproductive years. Therefore, births often occur after the dissolution of a first union. Previous research suggests that men and women differ in their re-partnering patterns, and has often found a re-partnering advantage for men. This study analysed the role of sex differences in re-partnering for sex differences in total fertility achieved after first union dissolution. We use Finnish register data to separately document all marital and cohabiting unions and all births which occur after the first union dissolution of four full birth cohorts up to age 48 for men and women. We decompose the sex difference in the summed fertility occurring after the first union dissolution up to age 48 into two parts: one rate component owing to sex differences in birth rates and a compositional component owing to sex differences in the share in re-partnered unions. On average, the post-dissolution fertility of women was higher than that of men. Women see a re-partnering advantage at early ages, while men have a re-partnering advantage at later ages. Tertiary educated men who dissolve a first childbearing union have higher post-dissolution fertility than their female counterparts and, for this group, a male ‘re-partnering advantage’ across the life course accounts for a substantial part of this sex difference.