Unintended benefits of parental son preference: sibling gender composition, personalities, and eldest daughters’ income

Abstract

This study revisits the identification of son preference, distinct from traditional measures of socioeconomic disparities between eldest sons and daughters. We focus on sibling gender composition, specifically, how having a younger brother, rather than a younger sister, affects the eldest daughter’s income in China. Leveraging the exogeneity of firstborn sex as an instrumental variable and using data from the China Family Panel Study, we uncover a counterintuitive finding: eldest daughters who have younger brothers experience a significant 10% increase in income. Further analysis suggests this increase is not driven by superior spousal characteristics but may be linked to personality development influenced by parental son preference. These results highlight the complexities of son preference and reinforce the ongoing need for gender equality policies at both national and family levels, despite the counterintuitive positive correlation with income.