Some countries have responded to shrinking populations with policies to attract migrants, especially younger people who can fill gaps in labour forces. By the 1970s, the fertility transition had occurred in Australia, Japan, and all highly developed countries in Europe and North America. Fertility in China fell sharply in the 1970s in response to policies to promote later and less frequent childbearing, and the introduction of the country’s 1979 family planning policy, which generally limited couples to one child.