Should we have a second child?

That is the question that bothers Xu Ying, a 32 year-old Shanghai mother.

A woman pushes a baby carriage across a street in Shanghai. [Photo / FOR CHINA DAILY]

"I want to have another baby, but my husband disagrees," said Xu, who has a 5-year-old daughter.

"It does a lot of good to have more children in a family. My daughter will not be lonely. And when we grow old, there will be less pressure on them looking after us together," she said.

But the dream sometimes has to make way for reality.

"My husband and I are both very busy. If I want to have a second child, I'll have to quit my job and take care of two children. And that means we will lose part of our income," she said.

"Having a second child is a difficult decision to make," she said.

Like Xu, many young couples in Shanghai are reluctant to have a second child despite being eligible. But they are being encouraged to have a second child by authorities who are trying to balance out an increasingly aging population.

"Currently, the elderly account for about a quarter of the local registered population, while children under 14 are only 8.6 percent," said Huang Hong, director of the Shanghai Population and Family Planning Commission.

She said that the shortfall in children will work against the city's sustainable development.

By the end of September, Shanghai had a population of 23.7 million, with roughly 14 million registered residents and 9.7 million migrants.

In 2011, about 3.5 million registered residents were aged over 60, and 2.3 million of them were over 65, according to the Shanghai Population and Family Planning Commission.

The number of people aged over 60 will rise by 200,000 a year until 2015, when they will account for one-third of the total registered population.