A little-known enforcement policy helped turn China's one-child policy into a powerful fertility force.
The findings published Friday point to why fertility dropped so sharply decades later. The policy arrived in 1979 and 1980, but fertility changed little at first. The sharp decline came in the 1990s, when China introduced a one-vote veto that tied local officials' career advancement to birth control targets. The tactic accounted for nearly half of the 1990s fertility drop, pushing births below the roughly 2.1 replacement rate. Stricter enforcement was linked to greater intrauterine device use and later induced abortions, though the initial birth decline was tied mainly to enforcement.