Determining and Transmitting US Citizenship
Your child is an American citizen if he or she was born in the USA.
Your child is also a citizen if he or she was born abroad and both parents are US citizens at least one of whom resided in the US or possession.
If only one parent is a US citizen, that parent must have been physically present in the US or possession at least five years prior to the child's birth, at least two of which were after the age of 14.
Different rules apply for children born out of wedlock or born before 1986.
Provided here is a Table of Transmission Requirements for children born abroad to an American mother and/or father. Note that since June 12, 2017, new rules apply for children born to unwed American mothers.
As a general rule, children born abroad to a US citizen parent or parents should have their birth registered at the nearest US consulate before age 18.
Your child born abroad may perhaps not qualify for US citizenship at birth because the American parent(s) has not satisfied the US presence requirement. There are two methods for possibly having your minor child (under age 18) naturalized as a US citizen: The Child Citizenship Act of 2000 (child immigration) and naturalization under Section 322 (using Form N-600K). One or both of these methods may be applicable in your case.
Updated November 11, 2017