There are essentially four ways for a child of a U.S. citizen born outside the U.S. to acquire U.S. citizenship from their father or mother. In these cases, the child’s year of birth, whether born in or out of wedlock, whether the U.S. parent had citizenship at the time of birth, how many years the U.S. parent lived in the U.S. and at what age, and whether the U.S. parent intends to immigrate to the U.S. soon with their family, among other factors, are especially important.

Specifically, for a child of a U.S. citizen to acquire U.S. citizenship, the following options exist:

• Automatic acquisition of U.S. citizenship at birth. If the child was born during marriage after November 14, 1986, to a U.S. parent who lived in the U.S. for five or more years before the child’s birth (at least two of which after the parent turned 14), then the child is automatically a U.S. citizen. Even if no action is taken to register the child with U.S. authorities, the child will be a U.S. citizen and can obtain a U.S. passport at any time in the future. Exact requirements vary for those born before November 14, 1986, those born out of wedlock, or those born to two U.S. parents.
• Acquisition of U.S. citizenship under Section 322 of the Immigration and Nationality Act. If the U.S. parent or a U.S. grandparent of the child lived in the U.S. for five or more years in the past, at least two after turning 14, the child may apply for U.S. citizenship under Section 322 of the INA, provided the process is completed before the child turns 18. A brief trip to the U.S. is required, but the child or parents do not need to intend permanent immigration.
• Acquisition of U.S. citizenship under Section 320 of the Immigration and Nationality Act. If the child immigrates with the U.S. parent who has legal and physical custody before turning 18, the child can immediately become a U.S. citizen upon arrival in the U.S. with an immigrant visa. Note that the U.S. parent must intend to immigrate to the U.S.—staying temporarily, e.g., a week in a hotel, is not sufficient for the child to become a citizen.
• Acquisition of U.S. citizenship through the traditional naturalization process. If the child is already over 18 and has not acquired citizenship, they must go through the green card process. The U.S. parent must petition for the child’s immigration to the U.S.—a process that can take many years if the child is over 21 or married. After immigrating, the child must live in the U.S. for five years before applying for naturalization.