expression, noun
biological parent; real parent
Refers to one's birth parent, as opposed to a stepparent, adoptive parent, or foster parent. Often used in contexts discussing family background or legal parentage.
彼は実の親に会ったことがない。
He has never met his biological parents.
実の親と養親の両方と交流がある。
She is in contact with both her biological parents and her adoptive parents.