Conditions for applying for a second-child birth certificate In mainland China, if you want to have a second child legally, you first need to obtain a second-child birth certificate. The prerequisite for obtaining a birth certificate is to meet the conditions stipulated by the state. At present, people who can have a second child mainly include the following two situations: 1. Both husband and wife are only children. 2. Both husband and wife have given birth to one child, and one of them is an only child.