Proposals under discussion would replace the population-control policy with one called “independent fertility,” allowing people to decide how many children to have, the person said.

The decision could be made as soon as the fourth quarter, the second person said, adding that the announcement might also be pushed into 2019.

The policy change would close the book on one of the largest social experiments in human history, which left the world’s most-populous country with a rapidly ageing population and 30 million more men than women.

The policies have forced generations of Chinese parents to pay fines, submit to abortions or raise children in the shadows.

The US and other Western nations have criticised the coercive measures required to enforce the birth limits, including steep fines, sterilisation and forced abortions.

The 2015 shift toward a two-child policy was part of a gradual effort to loosen the birth limits over the years as China’s working-age population began to decline.

An initial feasibility study was submitted to Premier Li Keqiang in April, according to one of the people familiar with the discussions.

That study found there would be “limited” benefits to lifting birth restrictions nationwide. Li requested more research on the social impact of scrapping the policy altogether, the person said.

Neither the State Council Information Office nor the National Health Commission immediately responded to Bloomberg’s requests for comment on Monday.

The move underscores growing concern among Chinese policymakers that more dramatic action is needed three years after allowing all families to have two children instead of one.

Births fell 3.5 per cent to 17.2 million nationwide last year, according to the Bureau of National Statistics, erasing almost half of the increase in births caused by relaxing the policy.

China’s ageing society will have broad consequences for the nation and the world, weighing on President Xi Jinping’s effort to develop the economy, driving up pension and healthcare costs, and sending foreign companies further afield for labour. The State Council last year projected that about a quarter of China’s population will be 60 or older by 2030, up from 13 per cent in 2010.

“The low birth rate and low number of newborns from the previous two years after the two-child policy sent a strong message to the decision-makers that the young generation has a weak willingness to have more children,” said Chen Jian, a former division chief at the National Family Planning Commission, who is now a vice-president of the China Society of Economic Reform.

“China’s population issues will be a major hurdle for President Xi Jinping’s vision of building a modernised country by 2035.”

In March, China removed the term “family planning” from the name of the newly consolidated National Health Commission – the first time since 1981 that no agency bears the name. Xi and Li also omitted any reference to the phrase from key policy reports in recent months.

While China credits birth limits with helping to launch a decades-long economic boom under Deng Xiaoping, they have also exacerbated demographic imbalances, with many parents choosing to abort female foetuses.

China has 106 men for every 100 women, compared with 102 globally, according to the CIA World Factbook.

Such moves have done little to increase the fertility rate, with many parents concerned about the costs of raising additional children in a society accustomed to focusing family resources on one. Nonetheless, Chinese policymakers have resisted calls by economists and demographers to relinquish control amid concerns over the impact of a sudden increase in births or older parents angry about missing the chance to expand their families.