According to data released by China's National Bureau of Statistics, China's newborn population in 2015 is 16.55 million, 320,000 less than the year of 2014. The National Health and Family Planning Commission responded that the decline is mainly due to the influence of zodiac preference and a decrease in the number of women of childbearing age.

The "selective two-child policy" has been gradually implemented in China since 2014. 2015 is the second year after the policy was fully implemented. Thus, the decline of the newborn population has attracted a great deal of attention. Some critics said it proved that the effect of the policy is far lower than previous estimations.

In response to that concern, a representative from China's National Health and Family Planning Commission said that two factors are largely responsible for the decline of births in 2015.

Firstly, there is the influence of zodiac preference. As 2015 is the year of the goat, some Chinese believe this year will bring bad luck. Some families have therefore postponed their childbearing plans, especially those in northern regions of China. After July 2015, there was an increase in pregnant women registering in hospitals to give birth in the year of the monkey. For example, the number of pregnant women in Beijing in July 2015 increased by 21 percent compared with the same period the previous year.

The decrease in the number of women of childbearing age is another factor that influences birth rate, according to the representative. Since 2011, that number has been on the decline. The number of women aged between 15 and 49 decreased by about 5 million over the previous year, while the number of women aged between 20 and 29 decreased by about 1.5 million.

The representative also said that births of second children increased significantly in 2014 and 2015, while births of first children decreased. The numbers of newborn first children and second children were respectively 10.56 million and 5.11 million in 2013, 9.72 million and 6.06 million in 2014, and 8.86 million and 6.52 million in 2015. The number of newborn second children has increased by 1.41 million since 2013, thanks to the selective two-child policy.

The representative concluded that the newborn population in 2015 was within the expected range. He also forecasted that the total newborn population will range from 17.5 million to 21 million from 2016 to 2020.

China's family planning policy was first introduced in the late 1970s to rein in the surging population by limiting most urban couples to one child and most rural couples to two children, if the first child born was a girl. The policy was later relaxed to say that any parents could have a second child if they were both only children.

The one-child policy was further loosened in November 2013 after the Third Plenary Session of the 18th CPC Central Committee, with its current form stipulating that couples are allowed to have two children if one of them is an only child.

According to the new family planning law, which was amended by the national legislature in late December, couples are allowed to have two children starting Jan. 1, 2016, ending the one-child policy that had existed for decades.