China's demographics are characterized by increasing median age at the time of first marriage, declining marriage rate and increasing divorce rate. According to the seventh national census results announced in 2021, China had 220 million unmarried people, accounting for 13.3 percent of the people aged 20 or above.

Most of the people who got married in 2013 were aged between 25 and 29. But in 2020 an increasing number of people chose to tie the knot after 30. In fact, the number of couples aged between 30 and 34 getting married increased from 11.3 percent in 2010 to 19.3 percent in 2020. And the number of marriages registered dropped from 13.47 million in 2013 to 8.13 million in 2020－with 4.33 million divorces.

The skewed sex ratio is one of the main reasons for late marriage and the declining marriage rate in China. Last year, men outnumbered women by 34.9 million－and there were 17.52 million more men of marriageable age (between 20 and 40) than women. More precisely, China has 108.9 men of marriageable age for every 100 women.

The singles demographic phenomenon has two main characteristics. One, people above 15 who live in urban areas are more likely to be single than their rural counterparts, because of the hustle and bustle of urban life. Two, people with higher education are more likely to remain single in their 20s, for they have to spend four years or more pursuing higher education.

Although education and age are important criteria for people choosing a partner, getting married is essentially an economic decision, with the costs and benefits of a marriage playing a key role in such a decision.

First, housing is a big problem that couples need to solve before getting married. But because of the sky-high housing prices and rising housing rents, young people, especially those in first-tier cities, are more likely to be struggling to earn enough money to buy (even rent) a house. In addition, the rental housing market's development has not only been relatively slow but also China's average housing price-to-rent ratio, or the ratio of housing price per square meter to the rent per sq m, is around 590, compared with the global standard of 200 to 300.

Second, although getting married has traditionally been a major decision for Chinese families, having children has become an equally, if not more, important decision for couples, because of the high costs of raising a child, especially the high cost of education.

The intense competition to get children admitted to a "good" school means parents need to spend huge amounts of money and energy on their kids' education despite the government introducing some policies, including the "double reduction" policy, to ease the education burden on students. This could also be prompting people to not marry early and, even if they do so, not have children.

And third, due to the rising numbers of well-educated and financially independent women, quite a few women who prefer a "better quality" life consider marriage more of an option than a necessity.

According to the Outline for Women's Development in China (2011-20), the country has basically eliminated the gender gap in primary and secondary education. Also, the proportion of women is higher than men in all areas of higher education－and female students accounted for 51 percent and 58 percent of all undergraduates in colleges/universities and adult programs.

Thanks to their higher level of education, women are playing a bigger role in the labor market－women's employment rate is 80.5 percent, accounting for 43.5 percent of the total employed population. As such, unlike in the past, marriage is no longer a necessity for some women.

Although the traditional family model has changed, married women are still expected to share most of the responsibilities of raising a child, which makes it difficult for them to balance family and job. Some women could even lose their jobs for seeking maternity leave. So to prevent job loss, many well-educated women refuse to give birth, even to get married.

The rapidly rising aging population and the falling marriage and fertility rates are interconnected. While the skewed sex ratio is making it difficult for many men to find a partner, many well-educated people, especially women, are choosing to remain single or tie the knot at a later age, with quite a few of them choosing to not have kids.

But since the millions of individuals who have chosen to stay single will not have the support of their spouse or children in old age, they will put greater pressure on China's eldercare system.

Therefore, the government should remove the barriers preventing people from getting married or having children, by regulating housing prices and the rental housing market, and providing more low-rent public housing in big cities. And to reduce the costs of running a family and raising children, it should reduce individual income tax, build more childcare centers and strengthen the employment security system for women.

The author is a professor at the Institute of Population and Labor Economics, Chinese Academy of Social Sciences.