The Immigration and Nationality Act defines the ability of one or both U.S. citizen parents to transmit American citizenship to a child born abroad. This ability is based primarily on the citizenship of the parents, their physical time(s) in the U.S., and their relationship status at the time of the child’s birth. The requirements are outlined here:

• If both parents are U.S. citizens and the child is born in wedlock, they must have resided in the U.S. at some time prior to the child’s birth.
• If one parent is a U.S. citizen and the child is born in wedlock, the U.S. citizen parent must have been physically present in the U.S. for five years prior to the child’s birth, two of which must be after the age of 14.
• If the child is born out of wedlock, transmission requirements depend on which parent is the U.S. citizen parent. If the mother is the U.S. citizen, she must have been physically present in the U.S. for 12 consecutive months prior to the child’s birth. If the father is the U.S. citizen, he must have been physically present in the U.S. for five years prior to the child’s birth, two of which must be after the age of 14. For either parent, additional requirements to establish the blood relationship between parent and child and to assure support for the child may apply.