When Individual Meets Megacities: How Personal-Structural Interactions Drive Ultra-Low Fertility in China

Fan Zhang , Universitat de Barcelona

This study investigates how individual socioeconomic conditions interact with urban structural constraints to produce ultra-low fertility in China's megacities. Using four waves of Chinese General Social Survey data (2017-2023) covering 11,947 urban residents, we examine Beijing and Shanghai, where fertility has dropped to approximately 1.0—significantly lower than other Chinese cities. Building on classical fertility transition theories, we emphasize how megacities' unique structural characteristics—extremely high living costs, intense competition, strict hukou barriers, and limited public resources—moderate the effects of individual factors on fertility decisions. We propose three core mechanisms: constraint amplification, where identical factors produce stronger fertility-suppressing effects in megacities; effect reversal, where factors that typically promote fertility may become fertility-suppressing due to higher opportunity costs; and dual constraints, where interactive effects between individual characteristics and urban structure create compounded disadvantages. Our analysis stratifies samples by childbearing status and employs multiple regression models, interaction tests, and Oaxaca-Blinder decomposition to identify dominant factors, synergistic effects, and intention-behavior gaps. We expect housing constraints and time pressures to emerge as primary fertility suppressors, with non-local hukou status creating compounded disadvantages when combined with economic constraints. Megacities are anticipated to show substantially larger gaps between fertility intentions and actual behavior. These findings suggest megacities require differentiated fertility policies addressing housing affordability, working hour limits, hukou reform, and childcare expansion.

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 Presented in Session 107. Childlessness and Late Parenthood