According to the 7th National Population Census of China, the estimated rate of childlessness for women aged 49 is 5.16% in 2020, lower than that reported in the European Union (19%) and in the United States (11%). The heterogeneity of childlessness in China is increasing, showing distinct differences regarding to period, cohort, education, place of residence, and regions. The childlessness level of women aged 49 with high levels of education, living in cities and regions with ultra-low fertility levels is much higher. Factors like the acceleration of urbanization, the continued popularization of higher education, and the ongoing trend of marriage and childbearing delay would further promote the rise of the childlessness level. Given China's low share of non-marital births and third births and above, the continuous rise of childlessness level would have a stronger negative impact on the newborn population and total fertility rates, thereby affecting China's ability to maintain the aimed suitable fertility level. The government should attach great importance to and address the issue in advance.

Based on the data from 2017 national fertility survey, this paper analyzes patterns and determinants of fertility intention in China under the universal two-child policy. The survey suggests that womens average ideal number of children is 1.96 and the average number of intended children is 1.76. For women born in the 1990s and beyond, the number of children they intend to have is 1.70, while for women who have not yet had any children, their intended number of children is 1.60, both are lower than the current average, indicating that there is room for a further decline in the fertility in China. About 9.3 percent of women intend to have three or more children. Among women who have at least two children, the corresponding proportion of women whose first two are girls is 45.6 percent. The regional difference of the intended number of children is more apparent. Sex-selective abortion inhibits fertility intentions and reduces the number of birth, however, in the case of unsatisfactory sex composition of children and tendency to continue to have children, son preference plays a role in strengthening fertility intention and increasing the number of births.

In preparing for fertility policy adjustment and implementing the “Two-child Policy for Couples One of Which Has No Siblings”，a national fertility intention survey was conducted in 29 provinces in China in August 2013. Survey results indicate that，currently，the ideal number of children is 1.93 in China. The reported ideal number of children in regions with 1 child，1.5 and 2 children policies are 1.84，1.98 and 2.01 respectively. For the couples both of which have no siblings，one of which has siblings and both of which have siblings，the reported ideal numbers of children are 1.79，1.83 and 1.95 respectively. For the couples one of which has no siblings with one child，the reported ideal number of children is 1.81. The overall sex ratio of reported ideal numbers of children is 104 males per 100 females in China. The sex ratio is 128 for those whose ideal number of children is 1 and 102 for those whose ideal number of children is 2. For the couples one of which has no siblings with one child，59% are“uncertain”about the birth timing of next child，20.5% plan to give a birth in one year，12.1% plan to give a birth in two years and 8.4% plan to have one in three years. Adjustment of family planning policy will help narrow the gap between fertility intention and fertility behavior，and it is highly unlikely that a nation-wide birth heaping would occur if the“Two-child Policy for Couples One of Which Has No Siblings”is well implemented.