What do Chinese citizens call illegal children?

In China, illegal children—those born outside of the family planning regulations—are often referred to as "black children" (黑户, hēi hù). This term underscores their lack of legal status and access to official rights, such as education and healthcare, due to the country's former one-child policy. The term reflects the challenges faced by these children in navigating a system that does not recognize their existence legally.