When the Chinese Communist party announced earlier this week that it would allow families to have three children, it justified it in terms of the need to “maintain China’s natural advantage in human resources”. Such an economic focus on fertility is nothing new. At least since the Reverend Thomas Malthus at the end of the 18th century, practitioners of the dismal science have puzzled over the connection between population growth, natural resources and improvements in long-term living standards. The latest question is how welfare systems will cope with ageing populations and increasing numbers of dependants.

China is not alone in facing a demographic transition. The global population is likely to peak this century or early in the next — fertility rates have declined pretty much everywhere. The number of children born per woman has fallen from about five in the 1960s to about 2.4 in 2018, according to the World Bank, slightly above the all-important “replacement rate” that marks the difference between a population getting older or younger. In sub-Saharan Africa, likely to deliver much of the population growth over the next century, fertility rates have dropped from about 6.8 children per woman in the 1970s to about 4.6 in 2018.

Those high birth rates in the 1970s inspired a revival of Malthusian worries that growing populations would swiftly exhaust natural resources. That opinions have shifted so far — worrying about the pace of decline rather than expansion — shows that while our anxieties over fertility may change they will always be with us in one form or another. The 1970s worriers had a point too: predictions of food running out have come to naught but the damage to biodiversity and the environment is obvious.

Gently declining birth rates are nothing to worry about. Rich countries in Europe and Asia have faced these trends for decades without a drop in living standards. Immigration from poorer countries has, no doubt, helped but so has rising productivity, encouraging more women to work. Fewer children lowers dependency rates too, offsetting some of the increase in old-age spending; less needs to be spent on education even if more is spent on pensions and healthcare.

Lower fertility rates can reflect economic success: wealthier, freer women generally chose to have fewer children, instead spending more time and effort on just one or two. On the other hand, strict attempts to control fertility have led to egregious examples of failure and have required severe repression.

The Romanian dictator Nicolae Ceausescu’s attempt to increase birth rates — banning birth control, abortion and taxing childless people more — led to thousands of children in orphanages. After an initial plunge, China’s fertility rate dropped at a not-too-dissimilar rate from other poor countries despite forced sterilisations during the one-child era. Hong Kong and Taiwan followed similar trajectories though not covered by the policy.

Governments should concentrate on enabling women’s choices. Where birth rates drop dramatically it often reflects that something is interfering with people’s ability to make truly free choices. Patriarchal expectations of how women should care for both young children and elderly parents can mean some opt out of starting families entirely. A lack of access to childcare, discrimination against mothers at work, and the career “penalty” for taking time off for child rearing, also have an impact on fertility choices. Achieving real freedom of choice rather than maintaining “human resources” should now be the focus.