U.S. Code definition
Title 8, Section 1401, of the U.S. Code provides the current definition for a natural-born citizen.
• Anyone born inside the United States and subject to the jurisdiction of the United States, which exempts the child of a diplomat from this provision
• Any Indian or Eskimo born in the United States, provided being a citizen of the U.S. does not impair the person's status as a citizen of the tribe
• Any one born outside the United States, both of whose parents are citizens of the U.S., as long as one parent has lived in the U.S.
• Any one born outside the United States, if one parent is a citizen and lived in the U.S. for at least one year and the other parent is a U.S. national
• Any one born in a U.S. possession, if one parent is a citizen and lived in the U.S. for at least one year
• Any one found in the U.S. under the age of five, whose parentage cannot be determined, as long as proof of non-citizenship is not provided by age 21
• Any one born outside the United States, if one parent is an alien and as long as the other parent is a citizen of the U.S. who lived in the U.S. for at least five years (with military and diplomatic service included in this time)
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