Study finds common pattern behind 200-year global fertility decline

Researchers at Japan's RIKEN Center for Brain Science have identified a shared two-stage pattern in the long decline of fertility rates across 237 countries and regions between 1800 and 2020, despite wide differences in culture, political systems and geography. In the first stage, high infant mortality was accompanied by high fertility, and birth rates gradually fell as life expectancy improved. In the second stage, fertility declined more sharply as household incomes rose, prompting families to invest more heavily in the education of each child rather than in the number of children. Lead researcher Kenji Itao developed a model framing the transition as a trade-off between fertility and educational investment. According to the study published in Evolutionary Human Sciences, falling education costs and greater social mobility accelerated the shift. The researchers said ongoing fertility declines in developed countries are not inevitable, and that policies easing the burden of childrearing and education could help preserve reasonable fertility levels. No further details on policy recommendations were immediately available.