Family formation process in strong family countries

Uchikoshi, Fumiya and Ryohei Mogi. 2018. “Order Matters: The Effect of Premarital Pregnancy on Second Childbearing in Japan” Demographic Research 39: 1305-1330 [Replication package] doi:


Background: In Japan, although non-marital childbearing is uncommon in contrast to the trends observed in other countries, the number of premarital pregnancies has increased. While prior studies have examined the determinants of premarital pregnancy, little is known about its consequence on individuals’ subsequent childbearing.
Objective: The aim of this study is to investigate the effect of premarital pregnancy on a second childbirth in Japan.
Method: We use the Japanese General Social Survey Life Course Study data, which covers women ages 28-42 in 2007. We use discrete time logistic regressions to estimate the individual hazard of experiencing a second childbirth. Additionally, because being pregnant before marriage occurs selectively depending on individual demographic characteristics, we attempt to balance the propensity to experience premarital pregnancy by using propensity score matching.
Results: The results reveal that experiencing premarital pregnancy causes a higher likelihood of second childbirth at earlier and older ages, defined as month at risk starting from one year after the first birth.
Conclusion: Our results support the life course change hypothesis that predicts that premarital pregnancy, which is highly likely to be unintended, increases the hazard to bear a second child, possibly by relatively reducing women’s attachment to work lives and their opportunity cost to have a second child.
Contribution: Premarital pregnancy may affect women’s subsequent life course through the influence of the strong linkage between marriage and fertility and working culture in Japan. The results could be applicable to other East Asian countries.

Family demography and intergenerational inequality

Fujihara, Sho and Fumiya Uchikoshi. 2019. “Declining Association with Persistent GenderAsymmetric Structure: Patterns and Trends in Educational Assortative Marriage in Japan.” Research in Social Stratification and Mobility. 60: 66-77. doi:


This paper investigates the patterns and trends of educational assortative marriage in Japan. Using data from the Employment Status Survey and the Comprehensive Survey of Living Conditions of the People on Health and Welfare, we investigated the trends of association between husbands’ and wives’ educational attainment (481,144 couples) by applying log-linear, log-multiplicative layer effects, and regression-type models. The analysis revealed that, in general, educational assortative marriage has decreased continuously. In terms of the log-odds ratios, the association of educational attainment between spouses for women born between 1975 and 1979 decreased by about 25%, in comparison with that of women born between 1950 and 1954. The regression-type models showed that the pattern of association was asymmetric while patterns of change were symmetric with respect to sex. We discuss what caused the decline in educational assortative marriage with a persistent gender asymmetric structure.