Wei-hsin Yu

Demographers and family researchers have long debated whether early childbearing has negative consequences on the offspring, but few have considered that the benefits of delayed childbearing (or the lack thereof) may not be universal. Using sibling data from the National Longitudinal Survey of Youth 1979 Children and Young Adults, we investigate how the relevance of mothers' age at childbirth to youth outcomes (academic performance, years of education completed, and psychological distress) may differ for youth whose early-childhood behavioral disposition (i.e., temperament) indicated varying degrees of insecure attachment. Results from family fixed-effects models, which take into account much of the unobserved heterogeneity among families, show that having an older mother is associated with improved educational and psychological outcomes for youth with a rather insecure early temperament. In contrast, mothers' age at childbirth hardly matters for children with a secure disposition. Further analysis indicates that the moderating effect of maternal age cannot be explained by the mother's first-birth timing, education, work status, income, or family stability. Older mothers' higher likelihood of prior child-rearing experience explains part of the older-mother advantage for temperamentally insecure children. However, the aging process, which equips older mothers with enhanced maturity, more calmness, and therefore greater capacity to overcome adversities, seems to account for the smaller detrimental effects of an insecure disposition on their children.

Much research has debated whether immigrants' health advantages over natives decline with their duration at destination. Most such research has relied on (pooled) cross-sectional data and used years since immigration as a proxy for the duration of residence, leading to the challenge of distilling the duration effect from the confounding cohort-of-arrival and age-of-arrival effects. Because longitudinal studies tend to use self-rated health as the outcome, the changes they observed may reflect shifts in immigrants' awareness of health problems. We illuminate the debate by examining how immigrants' mortality risk—a relatively unambiguous measure tied to poor health—changes over time compared to natives' mortality risk. Our analysis uses the National Health Interview Survey (1992–2009) with linked mortality data through 2011 (n = 875,306). We find a survival advantage for U.S. immigrants over the native-born that persisted or amplified during the 20-year period. Moreover, this advantage persisted for all immigrants, regardless of their race/ethnicity and gender or when they began their U.S. residence. This study provides unequivocal evidence that immigrant status' health protection as reflected in mortality is stable and long-lasting.