Journal of Economic Perspectives · 2026 · [{"name": "Michael Geruso", "affiliation": ["National Bureau of Economic Research"]}, {"name": "Dean Spears", "affiliation": ["IZA - Institute of Labor Economics"]}]
中文摘要
就全球整体而言，平均出生率已持续下降数十年——从1950年的约5降至今天的略高于2。如今三分之二的人口生活在出生率低于平均每两名成年人生育两个孩子的国家，这意味着低于维持人口规模（在无净迁移的情况下）所需的生育水平。本文评估低生育率是否可能作为一种全球现象持续存在。我们区分队列出生率与时期出生率：前者关系到代际间的人口变化，后者呈现某一时点出生率的快照，但对更长期的可能性或许提供较少洞见。在队列出生率已降至低位的地方，其后并未出现反弹。我们表明，终身无子女比例的上升与父母生育子女数量的减少，二者都促成了队列出生率的下降。我们讨论指出，鼓励生育政策可能对年度生育数据产生较大影响，却不会实质性改变女性一生中平均生育的子女数量。尽管未来出生率仍不确定，但我们依据证据得出结论：在长期视野下，持续的低生育率很可能是未来的图景。
Abstract
For the world as a whole, average birth rates have been falling for decades—from about 5 in 1950 to a little above 2 today. Two-thirds of people today live in a country where the birth rate is below an average of two children per two adults, which means below the fertility level needed to sustain population sizes (without net migration). In this paper, we assess whether low fertility is likely to persist as a global phenomenon. We distinguish cohort birth rates, which matter for generation-to-generation population change, from period birth rates, which present a snapshot of birth rates at a point in time, but may offer less insight on longer-run possibilities. Where cohort birth rates have fallen low, they have not subsequently rebounded. We show that both increasing rates of lifetime childlessness and smaller family sizes among parents have contributed to falling cohort birth rates. Pronatal policies, we discuss, can have large effects on the annual fertility data without substantially changing the average number of children women have over their lifetimes. Although future birth rates remain uncertain, we conclude from the evidence that, over a long horizon, persistent low fertility is a likely future.