Abstract
BACKGROUND: This study examines gender differences in early childhood cognitive development in rural China, focusing on the role of sibling structure. While gender disparities have narrowed in recent decades, concerns remain regarding unequal household resource allocation in low- and middle-income countries, particularly in contexts shaped by traditional son preference. METHODS: Data from 1,320 children aged 3 to 7 years across 11 nationally designated poverty counties in the Qinling Mountain region of western China were analyzed. Cognitive ability was assessed using the Chinese version of the Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition (WPPSI-IV). Descriptive statistics and multivariate regression models were employed to investigate the associations between sibling structure and cognitive outcomes by gender. RESULTS: A negative association was observed between the number of siblings and cognitive scores, with a substantially larger effect for girls. Gender disparities were also evident across sibling composition and age spacing: girls with older siblings, especially those within a three-year age gap, exhibited lower cognitive scores than boys. With respect to birth order, both boys and girls demonstrated first-born and last-born advantages, though the cognitive benefits were less pronounced for girls. These disparities are likely shaped by resource dilution, reduced parental investment, and lower educational expectations for girls. CONCLUSIONS: Gender differences in early cognitive development persist in rural western China and appear to be significantly influenced by family structure. Traditional norms may continue to affect intra-household resource allocation, often to the detriment of girls. These findings underscore the need for gender-sensitive policy interventions aimed at promoting equitable early childhood development and supporting long-term human capital accumulation. TRIAL REGISTRATION: Not applicable.