Derived citizenship refers to the process by which certain individuals automatically acquire U.S. citizenship as a result of a parent’s citizenship or immigration status. It is an immigration law concept that allows a child to derive citizenship from a parent who has become a naturalized U.S. citizen. The Child Citizenship Act of 2000 provides information on what proof and documents are required before a child can derive U.S. citizenship. If the child has a green card at the time the parent becomes a U.S. citizen, is under the age of 18, and lives with the parent, the child gains citizenship automatically. Adopted children are also able to become U.S. citizens if their parent naturalizes, so long as they show they were adopted before they turned 18, have a green card at the time the parent naturalized, the adoptive parent had custody of the child, and the adoptee was not married at the time. The derivative citizenship regulation applies to adopted children of U.S. citizens, as well as biological children. However, stepchildren are not able to derive citizenship from a stepmother or stepfather under this provision.