Estimating Causal Effects of Fertility on Life Course Outcomes: Evidence Using a Dyadic Genetic Instrumental Variable Approach

Working Paper: NBER ID: w30955

Authors: Boyan Zheng; Qiongshi Lu; Jason Fletcher

Abstract: The causal effects of fertility are a central focus in the social sciences, but the analysis is challenged by the endogeneity of fertility choices. Earlier work has proposed several “natural experiments” from twin births or gender composition of earlier births to assess whether having more children affects adults’ outcomes, though there are limitations to using rare (twins) and weak (gender composition) instrumental variables for fertility. This paper proposes a new “natural experiment” approach to assessing the causal effects of fertility by measuring the combination of couples’ genetics in predicting fertility—a dyadic genetic instrumental variable, where the key idea (exclusion restriction) is that the interactions of the couple’s genetics that shift the likelihood of fertility is unknown to the couples. We use a nationally representative sample of couples to examine the long-lasting effects of fertility on older adults’ life outcomes, including labor market outcomes, personality traits, and subjective wellbeing. We find that fertility reduces females’ extraversion and years of working and some evidence indicates that fertility reduces both males’ and females’ lifetime number of jobs worked.

Keywords: No keywords provided

JEL Codes: J10; J13; J22; J29


Causal Claims Network Graph

Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.


Causal Claims

CauseEffect
Fertility (J13)Decreased labor market participation among women (J29)
Fertility (J13)Decreased extraversion in females (J16)
Fertility (J13)Reduced lifetime number of jobs worked (males) (J26)
Fertility (J13)Reduced lifetime number of jobs worked (females) (J22)

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