About 700,000 Chinese couples in which one of the partners is an only child applied to have a second child by the end of August, and 620,000 of them got a permit, the National Health and Family Planning Commission said on Wednesday.

That's far fewer than previous estimates by the authority, which put the annual births increase due to the policy change at more than 2 million.

More than 11 million couples became eligible to have a second baby after the country decided in November to ease the family planning rules by allowing couples to have a second child if one of the parents is an only child. Previously, both the husband and wife had to be an only child if they wanted a second child.

To date, all Chinese province level areas except the Xinjiang Uygur and Tibet autonomous regions have implemented the new policy.

Lu Jiehua, a professor of demography at Peking University, said the lower than expected number of applications might reflect a changing perception of reproduction, particularly in urban settings, among those with a high education level.

Most of the couples that the policy affects are living in urban areas, he said.

In reality, childbirth for some is more of an economic issue.

Liu Yulin and his wife, both in their early 30s, are still trying to decide whether to have a second child.

"My first is a boy. I don't think I can afford to have another boy, for whom I have to buy housing," said Liu, who has an older sister.

The couple are white collar workers in Beijing, where quality education and housing remain expensive.

Apparently studies and analysis before the policy change could hardly match the real situation, said Lu, the professor.

The latest relaxation aims to address a rapidly aging society and to maintain a sustainable labor supply, he said.

Lu said that a careful analysis of new births next year under the new policy is required to assist future decision making, primarily when to introduce a comprehensive two-child policy.

"That probably will come in five years," he said.

However, Cai Fang, deputy director of the Chinese Academy of Social Sciences, the top government think tank, believes otherwise.

"It will be introduced in two years," he said in an interview with China National Radio earlier this month.

But the population authority disputed that claim, saying it has no timetable yet.

shanjuan@chinadaily.com.cn