A population-control policy isn't enough to face the challenges of an aging society, he said.

"The parents of an only child should rely on social welfare and insurance when they grow old," Yao said.

"Combining population control with the social security system is necessary in order to face the challenge of an aging society."

China's elderly population is growing. The Office of the China National Committee on Aging says the number of people aged 60 or above stood at 167 million in 2009, or 12.5 percent of the 1.3 billion people.

Yang Yansui, director of the Research Center of Employment and Social Security at Tsinghua University, told the Global Times that the social welfare and security system should serve as a tool to help adjust the population structure in order to meet the need for a healthy popula-tion so as to remain in line with global competition.

She also called for maternity insurance to be included in the social welfare system.

"The government should not only control population through forced measures but set a framework for population development, such as determining which sector of society should be encouraged to have more children and when is the best time to have a child, " Yan said.

But not all Chinese couples want to have children, as more and more 'dual income, no kids' families emerge.

Xie Ying, 31, told the Global Times that she and her husband have no plans to conceive due to pressure from work and the cost of living in major cities.

"I support the family planning policy because I don't think China can afford too big a population," Xie said. "It's too crowded."

But she also said that people may feel lonely when they grow old because more children may bring more happiness.

The family planning policy has been adjusted since it was introduced. In some provinces in China, if both of the parents are an only child they are reportedly permitted to have two children.

And the family planning policy does not cover ethnic minorities and some farmers whose first child is a girl.

Su Chang, a mother of two, had her second child last week. She told the Global Times that although the procedure is complicated, requiring her to submit some 30 files, including the marriage certificates of her parents, she was finally able to have a second child.

"It took me more than a month to get the birth certificate," she said. "But if permitted, I would have more, because I love to be surrounded by my children."