only child(男女都可以)复数：only children
the only child in one's family 都有 独生子女 的意思。不过多用only child.
parents who dote on their only child.
only children are sometimes spoilt.
而extra births就是“超生人口”，也就是我们平时说的“计划外生育”，也可以称为extra children /additional births。根据family planning policy(计划生育政策)，一般情况下每个家庭只允许生育一个孩子，也就是我们所说的only/single child(独生子女)。
the term “china one”refers to the child who was born after the 1980s, when china launched the one-child policy. not only are they the family’s only child, but they are also the family’s center of attention. their parents and grandparents would spare no efforts in taking care of them, and would give them anything and everything, as if they were the “emperor” of the family.
as a result, most children of the “china one”generation lack independence as they have become so reliant on their families for support. some parents even hired a maid for their children when they go to college. other unfavorable characteristics include: bad communication skills, rudeness, ungratefulness and self-centeredness.