31.   His parents divorced before he was born, he was adopted by his stepfather and he never met his biological father.

32.   His biological father probably was a bigamist.

33.   His biological father was not the man who had raised him, but a man he had never met, the actor Van Heflin.

34.   I continued trying to find my biological father, fighting through one bureaucratic barrier after another, to no avail.

35.   I know even less about my biological father.

36.   If Y markers do not match, then the two do not share the biological father.

37.   In this future society young women were valuable only as baby machines, identified by their red capes and the first name of the biological fathers.

38.   Johnson never knew his biological father, though he kept his last name.

39.   Jeannette never knew her biological father, and now she had lost her adoptive father.

40.   Joseph will be the biological father, a prospect that delights his mother.