The survey, jointly conducted by Radio Guangdong News Channel and a number of fertility websites, interviewed nearly 10,000 two-child familes, with 63 percent reporting feeling happier after the birth of a second child.

The major reason for the rise in happiness was seeing two children grow up together.

After decades of the one-child policy, many parents are believed to be concerned as to whether their first child could accept a younger sibling.

However, the survey found that 44 percent of children in two-child familes were fine with a younger sibling, and only 1.5 percent could not accept a sibling at all.

"Though having a second child is often described as tiring, it is not a burden but a happiness to see two children beginning to get along well and keeping each other company," said Zhu Yuzi, who worked for the survey team and is a mother of two.

Starting in the late 1970s, China's one-child policy ended on Jan. 1, 2016, when the government allowed all married couples to have two children.

In 2016, there were 18.67 million newborns in China, 11 percent more than in 2015, and about 45 percent of them were not a first child, according to the National Health and Family Planning Commission.

While a second child brought happiness to many families, it also produced several problems, mainly money and time pressure.

Wang Sha, 29, is mother of a five-year-old boy and a seven-month-old girl. She agreed that having siblings is good for children but said it was also stressful.

"It brings a big challenge financially, and it requires a lot of time to raise two children, so we will not have a third baby even if a policy allows us to do so," said Wang, a housewife in Beijing.

According to the survey, though 47 percent of parents have husbands that help more with the child-raising after a second child, 57 percent of wives said they had to quit their jobs to take care of the children.

Dong Yuzheng, director of the Guangdong Academy of Population Development, said the survey could assuage many people's concerns about having a second child, but it also showed problems that needed to be solved with assistance from government.

"Related issues, including employment policies, education policies and the establishment of various public facilities, should be properly designed under social governance," Dong said.