According to eugenic theory, women born in the 1980s are close to the best childbearing age (35 years old), and women born after 1980s, especially in urban areas, are mainly the only child of their family. Over the past two years, husbands and wives of childbearing age have not responded "positively" to the policy of allowing couples one of whom is the only child of their parents to have two children. This suggests the decision of allowing all couples to have two children, too, is not likely to lead to a baby boom.

As to women born in the 1970s, even if they were allowed to have a second child, not many of them would seize the opportunity because they are already past the best child-bearing age.

For women born in the 1980s, they are facing another fertility crisis. Although they are still in the best child-bearing age, many of them cannot afford or do not want to have a second child because of the huge cost of bringing up an "additional" (second) child. In fact, the high cost of rearing a child has forced many a couple to stick to the one-child social norm, even if they are eligible to have a second child.

And when it comes to women born in the 1990s, changed social situations have dampened their desire to have children, with the "no child" culture becoming increasingly popular among them.

Therefore, there is no reason to expect or fear a baby boom in China following the CPC Central Committee's decision. But going by demographic requirements, China needs a baby boom to, among others, cope with the aging population problem, correct the distorted population structure and build a promising and sustainable society.

The author is a professor at the Population Research Institute of Peking University.