For three decades it has been the subject of intense debate and rancour, preventing as many as 400 million births - mostly of baby girls. But China is now considering axing its one-child policy, a senior family planning official said yesterday, amid concerns about the gender imbalance and the ageing population.
Dr Zhao Baige, at the National Population and Family Planning Commission (NPFPC) said detailed studies into the environmental, social and other implications of changing the laws had begun.
Asked if there were plans to scrap the one-child policy, she said: "I cannot answer at what time or how [we will decide], but this has really become a big issue among decision makers. We want to have a transition from control to a slow down [relaxation], incrementally. The attitude is to do the studies, to consider it responsibly."
The controversial rules, which restrict most urban families to a single child but allow many rural couples to have two, were introduced to stop the world's largest national population from soaring out of control and outstripping resources.
But the policy has become divisive, owing to a complex set of exemptions, enforcement inconsistencies and financial penalties, which allow some people to have larger families than others. Several experts have called for a move to a uniform two-child policy.
The government says its current policies have resulted in 400m fewer births. It is worried that reform would result in a drastic increase in the population of 1.3bn.
"They see population control as essential to stable economic growth; they are really afraid of it taking off and many officials have said to me they can't just have a free-for-all," said Dr Therese Hesketh, an expert on China's one-child policy at the Institute of Child Health at University College London. "I suspect what they may do is move to a two-child policy across the board. It's been so divisive that some can have two and some can have one. It's not so bad in the cities, where the policy has been pretty strictly imposed, but at county-level [in the countryside] it can be so disparate."
Hesketh added that officials also feared the prospect of an ageing society in which one worker was left to support two parents and four grandparents. China's fledgling social security system means the vast majority of old people are dependent on their families.
At its peak in the 1960s, the fertility rate was 5.8 babies for each woman of childbearing age thanks to Mao Zedong's promotion of large families for the sake of the nation. It soon plummeted to 2.9 when his successors made contraceptives and abortion widely available.
The one-child policy quickly cut it further, to just 1.8 - well below the replacement rate of 2.1. The Chinese government has predicted that the population will peak at 1.5bn in 2033.
While there is no prospect of controls being completely lifted, changes could be rolled out region-by-region, or introduced for particular households. Some areas now allow people in their second marriage to have another baby if their spouse has none, and permit couples without siblings to have two children.
But officials are nervous of announcing potential amendments to the rules in case people pre-empt them. Discussions about relaxations in 1983 are believed to have led to the birth of up to 30m more babies that year.
Zhao acknowledged the problems posed by the cultural preference for boys and warned that in future the use of ultrasound to predict the sex of a child - and terminate female foetuses - could become "a big issue". China already has 118 male births for every 100 female - above the global normal ratio of between 103 and 107 boys for every 100 girls - although experts say family planning laws are only partly to blame.
The government is to expand a pilot scheme to encourage families to value girls by introducing special social and economic benefits for them, as well as by banning sex-selective abortion.
It is also training family planning workers to address the underlying causes of excess male births, and to promote its policies more effectively.
"In the 1970s it was always the same language- 'One child is best'. Now it about giving information on contraception," said Zhao, adding that attitudes had changed, with 60% of young women saying they wanted a maximum of two children.
But while many Chinese accept limits on family size may be necessary, there is still substantial bitterness about the restrictions and the system's inequity - such as fines or "compensation fees", which can be crippling for many families, but almost insignificant for the wealthy. That has spawned widespread resentment, and promises by the government of tougher fines and credit blacklisting for celebrities and the wealthy who flout the rules.
Experts say that the system depends in large part on self-enforcement, with many women aborting second or third pregnancies without the authorities ever knowing, because they cannot afford the fines or fear losing their jobs.
While the rules are far less harshly imposed than before, the monitoring and punishment of infringements varies. The NPFPC said yesterday that two officials had been detained for three to six months, and one official sacked, for forcing women in Shandong province to have abortions and sterilisations, a case that became a cause celebre.
Chen Guangcheng, the activist who tried to launch legal actions on behalf of the victims, is still imprisoned.
