Fertility trends across migrant generations reexamined: insights from Finnish register data

Abstract Migrant descendants in several European countries show increasingly lower fertility rates, sometimes even lower than native-born peers—a pattern defying conventional expectations that migrant descendants either maintain origin-country patterns or converge toward host-country norms. Using Finnish register data (1985–1994 birth cohorts), we analyze first-birth timing across six ancestry groups spanning three migrant generations: 1.5, second, and 2.5 (children of mixed or exogamous couples). Entry into parenthood occurs progressively later across these generations, with the 2.5 generation surpassing even native Finns in postponement. We tested four mechanisms—urban residence, educational investment, economic instability, and barriers to union formation—but none explained the delay. Our study contributes to the literature by, first, underscoring the limitations of the convergence narrative to account for the fertility behaviour of migrant descendants and, second, by drawing special attention to the 2.5G as a sui generis group whose behaviour requires further conceptual and empirical attention.