Snow Bai, 38, loves children. Already mother to a four-year-old boy, she wouldn't mind having another child, but 'only in an ideal world'.
In reality, she won't even consider it. Under the one-child policy, she would lose her job as a state employee if she becomes pregnant again. But more to the point, she said, is the high cost of bringing up a child in Beijing.
She and her husband spend about 40,000 yuan (HK$48,700) per year, or 10 per cent of their joint salaries, on sending their son to a private kindergarten.
'And to think of primary, secondary and university education ... we just can't afford another one,' said Bai, an accountant.
'Besides, I don't think I have the time to look after two.'
Bai's predicament is not unusual, especially among the mainland's middle class who in recent years have seen more of their household budgets squeezed by inflation and increasingly unaffordable housing.
As China remains the world's most populous country with 1.34 billion people, it is hard to imagine that only 50 years ago, the population was half its current size - 667 million.
Then, women were on average having five to six children and the population was growing rapidly.
It was against such a backdrop that the leadership first introduced campaigns to encourage fewer children and later enforced the one-child policy - which limits most urban couples to one child and some rural families to two - in 1980 out of fears of a population explosion.
But three decades on, many women like Bai do not even wish to have a second child even if they had the chance.
Today, China has one of the lowest birth rates in the world, with a productive workforce that is ageing into retirement faster than it can be replaced by younger workers - a factor that academics say could pose a serious threat to its economy, social stability and political rule. With the United Nations saying that the world's population will hit 7 billion today, it is hard not be alarmed at the unprecedented speed at which the world's population has grown in the past few decades.
According to the UN, the world's population has more than doubled in the past 50 years, from three billion in 1960 to six million in 1999.
It has taken only another 12 years to reach seven billion.
Compare this to the hundreds of thousands of years it took for the population to reach the first billion in 1804 and the picture looks bleak indeed.
China has long boasted of its contribution towards controlling the world's population by claiming that the one-child policy has prevented 400 million births since its implementation 31 years ago. The claim has been disputed by demographers, who say that the number of averted births is actually half the government estimate and that socio-economic changes lowered the birth rate before the policy was imposed. But an article in the official People's Daily last week said that without this policy, China's population would now be 1.7 billion and the world's population would have hit 7 billion in 2006.
Many scholars have been urging the government to relax the rule.
They say it no longer needs to artificially depress the already low birth rate as the country's demographic landscape has been dramatically altered in recent decades by rapid socio-economic changes.
Census results from last year paint a worrying picture of a slowdown in population growth, low fertility and accelerating ageing, which suggests that the country's phenomenal growth could be slowed by a greying society, a dwindling labour pool and pressure on social security.
According to census figures, the country's population grew at the rate of 0.57 per cent between 2000 and last year, about half of the 1.07 per cent rate in the previous decade and one-fifth of the level in 1970.
The figures also implied the total fertility rate - the average number of children a woman can expect to have in her lifetime - has further shrunk to 1.4 from 1.82 a decade ago, well below the level of about 2.1 that allows the population to replace itself.
In 1970, when the government began looking into controlling population growth, the fertility rate was 5.5. But demographers say during the past two decades, the mainland's fertility has dropped to a level that is among the lowest in the world.
The census also found a trend of rapid ageing of the population while the young population continued to shrink, suggesting a heavier burden for the working young to take care of the old. Citizens aged 60 or more accounted for 13.3 per cent of the total population, compared with 10.3 per cent in 2000, while those aged 14 or younger declined to 17 per cent from 23 per cent during the past decade. By 2050, one-third of the population is forecast to be aged 60 or over.
Given these trends - and growing evidence that socio-economic transformation rather than government policy is depressing the birth rate - more and more people are starting to question the wisdom of continuing the one-child policy, which has exacted high social and economic costs on society.
The ills of the one-child policy are well-documented - a disproportionately high number of male births due to sex-selective abortion, a rapidly ageing population without adequate government and family support, human rights abuses against women and the unborn through forced sterilisation and abortion.
Professor Wang Feng, director of the Brookings-Tsinghua Centre for Public Policy in Beijing, warned of a 'looming crisis' if the current population policy remains unchanged.
Thanks to low fertility rates since the early 1990s, he sees a sustained decline in new entrants to the mainland's workforce. During the past decade, the number of workers aged between 20 and 29 on the mainland has fallen by 15 per cent and it will shrink by another 20 per cent in the next 20 years, he said. Meanwhile, the number of people aged over 60 is forecast to double from the current 170 million to around 340 million by 2030.
In the absence of a wellestablished social security and pension system, the ageing population will not only put strains on a shrinking number of working young to support the elderly, but would likely threaten the country's economic prospects and pose unprecedented political challenges to the government, he said.
'Serious population ageing will pose a challenge to political governance, as we've seen in Greece and much of Europe. The situation in China will be more serious, given the drastic decline in the ratio between workers and the retirees,' Wang said.
'The government will not be able to extract the money and deliver its promises.'
In 2004, a group of scholars signed a petition urging the leadership to consider relaxing the one-child policy. Among them was Professor Zheng Zhenzhen at the Chinese Academy of Social Sciences' Institute of Population and Labour Economics, whose research in Jiangsu province suggests that even without the one-child restriction, the fertility rate on the mainland is likely to remain low.
From her survey of more than 18,000 women in six counties in Jiangsu - which permits couples in which one parent is an only child to have two children - her team found that among those eligible to have two children, only between 10 and 15 per cent went on to have a second child.
Among the same group, the ideal family size averaged out at 1.46 children, with a majority - 55 per cent - saying one child is best.
'Our research suggests that even if couples are allowed to have two children, it will have very little impact [on the overall population],' she said. 'They think the cost of raising a child is too high.'
But campaigning by scholars and some local governments for a relaxation of the policy has had little success. An article published this month by Caijing magazine said a pilot project that proposed allowing couples in five provinces to have a second child if one parent was an only child was shelved indefinitely.
Last week, People's Daily insisted the one-child policy will continue for at least another five years to 'maintain a low and stable birth rate'.
Wang said the reluctance to relax the restriction shows the ignorance and short-sightedness of policymakers. 'The policymakers are seriously unaware of what is happening in China and the world,' he said. 'Their mindsets are still stuck in the 1970s. This continued fear of population growth is based on a misconception of reality, is totally out of sync with time and is exerting a great cost to Chinese families and society.'
Others say that when the country's leaders issued an open letter announcing the one-child policy on September 25, 1980, they stressed it was meant to be a temporary measure that could be changed when the population pressure lessened.
'Our fertility rate is less than 1.5, and if you still say we need to restrict the population, that's short-sighted,' said Cai Yong, a demographer at the University of North Carolina.
'Instead of stepping on the brakes [on the one-child policy] they are still pressing hard on the accelerator.'