legitimate birth

例句：

1. 1. The baby was born in the hospital, and it's a legal birth.
   这个婴儿在医院出生，这是合法的。
2. 2. The couple had a legitimate birth certificate.
   这对夫妇有一张合法的出生证明。
3. 3.The government is trying to legitimize its birth control programs.
   政府正试图为其计划生育计划赋予合法性。