The family planning policy is facing a formidable obstacle spawned by progress - the rising affluence of an urban class.
From having more children abroad to paying huge fines outright, an increasing number of rich people and celebrities have been having two or more children in recent years, policymakers and sociologists say.
The government has not disclosed the number of people breaking the law to have more children, but Zhang Weiqing, the former director of the State Family Planning Commission, said the rich and famous who break the rules have cast a huge shadow over the policy, denting social equality and even stability.
Figures from local authorities show that women from the Chinese mainland gave birth to nearly 78,000 babies in the Hong Kong special administrative region from 2001 to last year, a choice the families made to skirt the restrictions, experts say.
"I delivered my second girl last year in Hong Kong, where I don't need a permit for the birth," said a Nanjing-based housewife, surnamed Li, whose husband owns a real-estate business.
Li said she paid 80,000 yuan to a travel agency in the capital of Jiangsu province for travel and medical expenses to "fulfill her dream family of a son and a daughter".
To address these challenges, the National Population and Family Planning Commission is said to be considering a new policy curbing nationals from having second or more babies outside the mainland.
"Due to the rising mobility of Chinese citizens and the social transformation from the country's reform and opening up from the late 1970s, it has become tougher to regulate the policy," Zhang said.
About a fifth of the people breaking the family planning rules are urban families, said Zhai Zhenwu, a sociology professor with Renmin University of China. The remaining are believed to be rural couples or migrant workers in cities.
Two years ago, the government increased the penalties by imposing a fine amounting to 10 times the annual average per capita income of the area the violators live in. The amount varies from 20,000 yuan in the countryside to 200,000 yuan in big cities.
"But this sort of fine is a piece of cake for the rich. So the government had to hit them harder where it really hurt - at their fame, reputation and standing in society," Zhai said.
The rich and famous have been shamed and stopped from receiving public honors. Pop stars can be barred from public shows or TV programs; and businessmen in the private sector, from government contracts.
Wang Difeng, a businessman in his 40s in Huizhou, a city in the affluent Guangdong province, said his second child was born in March. He had to pay a fine of 100,000 for flouting the rules.
"I don't care about the money. But from now on, I'm not entitled to any professional or social awards such as 'entrepreneur of the year', which I won three years in a row," he said.