birth name       
noun [ C ] uk/ˈbɜːθ ˌneɪm/ us/ˈbɜː˞θ ˌneɪm/
 原名,出生名
the name that you were given at birth, when this is different to your current or usual name
  El Greco is a Cuban trumpeter whose birth name is Jose Miguel Crego Castro. El Greco是一位古巴小号演奏家,他的原名是Jose Miguel Crego Castro。 
 Some transgender people feel great anxiety about being associated with their birth name. 一些跨性别人士非常抵触使用自己的原名。 
 - More examples
 - He was adopted at 13, but the adoption failed, and he went back to his birth name.
 - P. Diddy uses his birth name, Sean Combs, as an actor.
 - She has cast off her birth name and calls herself Ninel (Lenin spelled backwards).