Statistics on mainland children born out of wedlock are patchy at best. One of the few organisations to gather such information, a legal aid centre under the Shanghai Women's Federation, registered 43 such cases in 2003 - more than double the figure in 2001.

'It's hard to gauge the number of unmarried mothers because many hide their identities,' says Xia Xueluan, a sociology professor at Peking University. 'But from media reports and other surveys, we believe there has been an increase in recent years.'

The surge is widely attributed to young Chinese being more sexually active while remaining ignorant about contraception and safe sex. A huge mobile population also restricts officials' ability to enforce population policy. In major urban centres such as Beijing, the neighbourhood authorities that policed births have gradually lost power as cities increasingly rely on the labour of millions of migrant workers.

But among better educated, financially independent women, raising children on their own is an increasingly common notion. Consider Cissy Cui Xinxin, a 26-year-old branding specialist with a Beijing consultancy. Having grown up in a divorced family, Cui is disillusioned with marriage, although she hopes to have her own family. 'I love babies, but don't want to get married,' she says. 'If I can afford to raise a child alone, why not?'

Artificial insemination became a serious option - at least in northeast Jilin - when provincial authorities introduced an unprecedented law in 2002 allowing unmarried women to conceive with medical assistance. But the Health Ministry banned such procedures a year later, fearing it would erode traditional family values and undermine the social structure.

'From a humane perspective, we should respect unmarried women's right to have babies,' says Xia. 'But we have a larger male population than female. If we encourage women to have babies out of wedlock, there'll be an even larger group of single men and the gender ratio will be more imbalanced. It's bad for social harmony.'

Xia also points to practical and social pressures. 'It's not easy to raise a child alone,' he says. 'Many children can't get enough care from their mothers and have psychological problems. It's even worse to see these mothers give up their responsibilities after children are born.'

With her son now 13 months old, Lu feels guilty about her choice. She says Yang Yang is timid and sickly because she wasn't able to give him sufficient attention. To make up for the neglect, she quit her job in August and now looks after him full time. 'I was very selfish at the time,' Lu says. 'I was so desperate to be a mother that I ignored his future happiness. If I could choose again, I wouldn't give birth.'

Many single mothers don't think the same. A Beijing newspaper reporter who blogs under the name Ground Melon Pig defends her decision to keep her baby after breaking up with her boyfriend.

'It's not impulsive,' she writes on her popular blog called Words to My Baby on Sina.com. 'I know I'll face many difficulties in the future, but I believe they will be solved in the end.

'The view that children from a single-parent family will have psychological problems is already a form of prejudice against single mothers,' she says. 'Are children with quarrelling parents more psychologically healthy? It depends on each parent.'

The 28-year-old journalist started her blog in August, when she was six months pregnant, and has since attracted about 1.5 million hits.

Her comments have stirred heated debate about unmarried mothers. Many hail her decision as courageous, even dubbing her the 'spokeswoman for single mothers', but Ground Melon Pig has her share of critics, with some questioning her motivation and personal character. The journalist says the aim of her blog is simple. 'I want to call more attention to people in my situation,' she says. 'It's only in this way that we can solve some practical problems like the children's residency permits. Aren't there more humane solutions other than abortion and fines?'

Under birth-control regulations in Beijing, unmarried women must pay a 120,000 yuan fine to be allowed to deliver a baby and secure a hukou for the child. They also have to submit documents, including the results of DNA tests and a copy of the father's identity card. Even then, a quota system for issuing hukou papers means they may wait years before securing the child's residency permit. '[The fine] is too high,' says Ground Melon Pig. 'I'm not badly paid as a journalist, but I still can't afford it. All I can do now is to try to make as much money as possible.'

Single mothers on the mainland are also denied a range of social benefits. Unlike married women, they're not entitled to maternity leave or reimbursement of hospital delivery fees. Those working for state-owned enterprises are often further penalised for breaching their unit's birth quota.

Having taken four months' leave to look after her child, Ground Melon Pig now worries that she may lose her job when she returns to the government-controlled newspaper. 'My boss doesn't agree with my decision [to become an unmarried mother],' she says. 'Neither do some of my colleagues.

'I know there's slim hope of getting the same social recognition and welfare as single mothers in Europe. But I don't want to give up my effort. I believe society will become more tolerant.'