Even if the one-child policy was relaxed, almost half of Shanghai couples would be reluctant to have a second child, according to research.

Some 45 percent of families are put off by the high cost of raising children, a study released yesterday by the Shanghai Academy of Social Sciences found.

The report said local families spent 31,760 yuan (US$4,934) on their offspring on average last year.

That accounts for more than 50 percent of disposable income for 10 percent of the 1,200 families with children under the age of 12 polled.

Child-related expenses - including education, food and clothes - have put parents under great economic pressure. Some 35 percent of those surveyed felt it's a heavy burden to raise children.

The report also found that white-collar workers busy with work have little time and experience to look after their children.

About 30 percent of respondents said that they suffer great stress taking care of their children.

The researchers also discovered that locals with permanent residence certificate, or hukou, are less likely to have a second child, compared to those with residence permits.

"Locals have higher requirements for raising kids and non-locals have higher endurance to hardship," said Yang Xiong, an SASS researcher.

Researchers found nearly half of migrant parents have left their children alone at home, while only 36 percent of local families have.

"My parents take care of my daughter when my wife and I are at work," said local father Brady Wu.

Many non-local families are at a disadvantage as they have no such extended family support in the city, Yang said.

The report also found that nearly 13 percent of children aged under three have been left at home alone, with the figure increasing to more than 20 percent for those aged between three and six.

Yang said this is very dangerous and that children younger than 12 should never be left at home alone.