birth certificate certificate of foreign birth A certificate issued in some jurisdictions in the United States for foreign-born intercountry adoptees. The certificate of foreign birth serves as documentary evidence of the child's birth and the child's legal relationship to the adoptive United States parents. These certificates, however, do not serve as evidence of U.S. citizenship and must be supplemented by another document to prove citizenship, such as a Certificate of Citizenship, a United States passport or a Certificate of Naturalization. certificates of foreign birth