Derivative citizenship statutes go back to the beginning of the U.S. (although it has and continues to change. During the second session of the first Congress, the first act to establish a uniform law of naturalization included a derivative citizenship provision. Throughout the history of the U.S., different laws have imposed different requirements in order to derive U.S. citizenship through the naturalization of the parents.In general, every subsequent statute repealed in whole or in part the equivalent provisions of the prior statute. Judicial and administrative interpretations have found the citizenship statutes to confer benefits prospectively. In general, statutes governing the derivation of U.S. citizenship have always required a combination of qualifying events to take place before the child turns a certain age. The law that determines which requirements apply to a person is the law that was in effect at the time the "last qualifying act" took place, i.e. when the last material prerequisite was met. The minimum requirements shared by all derivative citizenship statutes up to the year 2000 were the naturalization of one parent and the acquisition of lawful permanent residence by the child. The Child Citizenship Act of 2000 removed the requirement of the naturalization of the parent, expanding derivation to those children of a U.S. citizen parent (whether native born or naturalized) if the children commenced residence in the United States by a certain age. In this respect, it was easier. The order in which the events required for derivation took place is generally immaterial, provided they all took place before the child turned a certain age. Thus, children who become lawful permanent residents after the naturalization of their parents could derive citizenship to the same extent as those who become lawful permanent residents before their parents' naturalization. however, that for derivative citizenship claims predicated upon parents who are legally separated, the order of events may nevertheless be relevant and sometimesw if only one parent gets naturalized, the requirements of derivation are not met. The Board of Immigration Appeals held that the Child Citizenship Act of 2000 is not retroactive for persons who meet all of the requirements but who were eighteen years or older on February 27, 2001, the effective date of the act.