SHANGHAI - Family planning authorities in Shanghai Municipality are encouraging couples who are both a single child themselves to have a second baby.

Single-child couples are allowed to have an additional baby under China's family planning policy.

However, a survey showed such couples are only having on average 1.2 babies in the city, Huang Hong, director with the municipality's population and family planning committee, told a press conference on Tuesday.

Economic conditions, the family environment, work pressures and fertility conditions are among the main factors that affect parents' decision of whether to have an additional child or not, said Huang.

She said 7,000 families in Shanghai have lost their single child so far, bringing great sorrow to the families.

Such families have different problems relating to social security, elderly care, medical services and spiritual counseling. The city has been considering establishing a special system to help these families, she said.

Like other cities in China, Shanghai is facing an aging population. According to the figures released at the conference, Shanghai has a registered population of 14.21 million, and 24.5 percent of them are 60 or over. The percentage is expected to reach 30 percent by 2015.

The family planning policy was first introduced in the late 1970s to rein in China's surging population by encouraging late marriages and pregnancies, as well as limiting most urban couples to one child and most rural couples to two children, if the first one is a girl.

Under the policy, most couples born in the 1980s in urban areas right now are a single child.