If you are over 18 years of age and born abroad to a U.S. citizen parent(s), your U.S. citizen mother and/or father may be able to transmit citizenship to you, if he/she meets the INA transmission requirements. Please consult the State Department’s Birth of U.S. Citizens Abroad and Acquisition of U.S. Citizenship webpages in order to determine if you are eligible to apply for a U.S. passport as the foreign-born adult son/daughter of a U.S. citizen parent. If you believe that you are eligible to acquire U.S. citizenship through a U.S. citizen parent(s), please follow the instructions above to apply for a U.S. passport.
In addition to a U.S. passport application form, you will also need to submit evidence demonstrating all of the following: 1) that you are the biological son/daughter of your U.S. citizen parent(s); 2) that your U.S. citizen parent(s) became a U.S. citizen(s) before your birth; 3) that your U.S. citizen parent(s) meets the physical presence requirements based on your date-of-birth; and 4) the marital status of your parents on the date of your birth.