Oh, of course i'll keep that in mind. Look, what happens if i'm not a U.S citizen?
You don't need to worry. If you're under that condition, the Social Security will ask you to see a current DHS document, such as Form I-551 Permanent Resident Card, for example.
Oh that's good there is many options. Look, going back on child's documents, once more, what can i do if i don't have a document, at hand?.
No problem. In that case, we can always accept some other document. For example, we can accept a state issued non driver identification card or in case being adopted, child's adoption decree.