Driven by economic development, ideational changes and family planning policies, the Chinese family has experienced significant change over the past several decades. Based on data from the 2018 wave of the China Family Panel Studies, this study analyzes China’s younger generations’ union formation and childbearing behaviors. The results show that although the average age of entry into a first marriage continues to rise, young people generally express a desire to enter into marriage and value the creation of a family. As premarital cohabitation became more prevalent, its determinants change from the “second demographic transition” model to the “pattern of disadvantage” model. The differences between cohabitors and non-cohabitors in premarital conception, premarital childbirth and divorce diminished in the recent cohorts. The findings suggest that the age of childbearing for Chinese women remains relatively early. The implementation of the “universal two-child policy” in 2015 has also encouraged younger women’s childbearing. Among those born in the 1980s, almost half have already given birth to a second child. The ideal number of children has declined across birth cohorts in China, especially for individuals with a higher educational level and urban hukou. In summary, changes in union formation and childbearing among Chinese youth imply that China will be facing a further rise in the first marriage age and a further decline in the fertility rate. However, voluntary singlehood will remain rare, and Chinese youth still value the importance of marriage and childbearing.