§ 416.1881. Deciding whether someone is your parent or stepparent.
(a) We consider your parent to be—
(1) Your natural mother or father; or
(2) A person who legally adopted you.
(b) We consider your stepparent to be the present husband or wife of your natural or adoptive parent. A person is not your stepparent if your natural or adoptive parent, to whom your stepparent was married, has died, or if your parent and stepparent have been divorced or their marriage has been annulled.
(c) Necessary evidence. We will accept your statement on whether or not someone is your parent or stepparent unless we have information to the contrary. If we have contrary information, you must show us, if you can, one or more of the following kinds of evidence that would help to prove whether or not the person is your parent or stepparent: Certificate of birth, baptism, marriage, or death, or decree of adoption, divorce, or annulment. If you cannot, you must tell us why not and show us any other evidence that would help to show whether or not the person is your parent or stepparent.