Changing Marital Fertility in Korea: Cohort Gaps in First-Birth Transitions After Marriage

• In Event: Family Section Open Call Paper Session

Abstract

South Korea has the world’s lowest fertility, and explanations that focus only on delayed or foregone marriage are increasingly insufficient. Because childbearing remains closely tied to marriage, it is important to ask whether recent declines in births stem mainly from changes in who marries (compositional change) or from changes in couples’ childbearing behavior after marriage. This study addresses that question by comparing first-birth transitions following first marriage across recent Korean marital cohorts. We analyze the Korean Labor and Income Panel Study (KLIPS). The sample includes respondents whose first marriage occurred between 2005 and 2024. Using event-history methods to account for right-censoring, we model time to first birth in months since marriage. We first compare Kaplan–Meier survival curves for marriages formed in 2005–2014 versus 2015–2024, and then estimate Cox proportional hazards models with covariates such as age at marriage, respondents’ and partners’ education, region, and religion. Both survival curves and Cox models show a clear post-2015 shift toward longer waits to a first birth. Marrying in 2015 or later is linked to a substantially lower first-birth hazard (about 0.66), and adjustment for covariates reduces this only modestly (about 0.71). Compositional change explains only part of the slowdown, indicating meaningful within-marriage behavioral change. Until ASA, we will extend the analysis to more clearly identify how much of Korea’s recent decline in marital fertility reflects changes in who marries versus changes in couples’ childbearing behavior after marriage.

Authors

• Paula S England, New York University-Abu Dhabi

• Wonjeong Jeong, New York University Abu Dhabi