what other documents can I use?
We can accept only certain documents as proof of U.S. citizenship . These include : Certification of Report of Birth DS-1350 ; Consular Report of Birth Abroad FS-240 ; U.S. passport ; Certificate of Citizenship N-560/N-561 ; Certificate of Naturalization N-550/N-570 .
Has the child lived outside of the United States for an extended period?
No they haven't