Abstract: The key to solving the population problem is to find out the root cause of the current low fertility willingness. Based on the opportunity cost theory, this paper introduces the explicit costs and hidden costs to conduct a theoretical analysis from the two perspectives of the cost and benefits of giving birth to the second child. Then based on the survey data, it empirically tests the factors that affect the fertility willingness of the second child. The findings show that such factors as the pain or danger during childbirth, the first child’s resistance, reduced leisure time, no one to care about the children, economic affordability, giving better and fewer births, and more family disputes all have a significant negative impact on the second child’s fertility willingness, which are the major factors restricting people’s child-bearing willingness of their own, among which, the explicit costs is the cause leading to the willingness of second child bearing of women generally lower than men. When studying the regional differences by taking into the consideration the human and social environments in different regions, it is found that the regional differences have a significant impact on the second child-bearing willingness. Therefore, the specific implementation of population policy should also take into account the regional differences.

Key words: second child predicament, fertility willingness, total release of two children, fertility costs