A bold family planning policy change was made at the recent Fifth Plenum of the 18th Communist Party of China Central Committee, which would allow all couples to have two children.

But many doubt the policy change would encourage more couples to have a second child. For one, the rising cost of raising a child, including the significant increase in education expenditure, has made many couples reluctant to have two children, with some deciding to not have even one. Education expenses comprise the largest single part of the cost of raising a child in cities. So the cost of education for a second child would double couples' burdens, the skeptics argue.

It is true that the rising education cost for a child, from elementary school to university, is the most important investment most Chinese families make. It is also true that the cost of raising two children will be much higher than bringing up only one. But that is not the whole story. The marginal cost of bringing up a second child can be low, because a family can fall back on many of the things it has already bought for the first child to provide for the younger sibling. As such, a two-child couple doesn't have to spend all over again on many things - except for food, education and some other necessities - to have what many believe an ideal family.

Siblings, older and younger both, are also a family's educational resources, for they provide each other company and help each other in the learning process. Their mutual interactions are a precious source of experience during their growing-up years, which is something a single child misses.

Siblings are not only the best playmates, but also help each other set familial and social rules, and build comity, which will help them become better human beings in the future. These experiences are very important for children in their growing-up years. In one-child families, however, children are deprived of these important experiences, not least because they are sheltered and pampered by their parents.

But to sincerely promote the two-child policy, the government has to increase its financial allocation for education in order to ease families' burdens. Only in this way can the government persuade more couples to have two children.

According to the decision of the Fifth Plenum of the 18th CPC Central Committee, the country will gradually expand the compulsory education system to cover high school education, and start exempting poor families from paying tuition fees. That's a welcome step.

That China's GDP crossed $10 trillion last year is reason enough for the government to increase its education budget so as to improve people's livelihoods. This will not only ease people's worries over the economic burden of raising children, but also prompt households to spend more in other areas and boost domestic consumption as a whole.

The plenum's decision also highlights the importance of developing the pre-school education sector. In fact, in many cities across China, sending a child to kindergarten is often far more expensive than paying for the expenses of a college student.

During the 12th Five-Year Plan (2011-15), the government fulfilled the goal of spending 4 percent of GDP on education. But it still lags behind developed countries, which on average spend about 5 percent of their GDP on education. China can start improving the education sector, for instance, by gradually spending more on the pre-school education sector, because it will reduce families education expenses and encourage them to have a second child.

The author is a senior researcher with the National Institute of Education Sciences. The article is an excerpt from her interview with China Daily's Zhang Yuchen.