Flores-Villar v. United States, 564 U. S. ___, 131 S. Ct. 2312, (2011)
The Supreme Court affirmed the Ninth Circuit’s decision in a case involving whether two former citizenship provisions in the INA violate equal protection. These sections imposed a five-year residence requirement, after the age of fourteen, on U.S. citizen fathers -- but not on U.S. citizen mothers -- before they may transmit citizenship to a child born out of wedlock abroad to a noncitizen. The Ninth Circuit, relying on the Supreme Court’s decision in Nguyen v. INS, 533 U.S. 53 (2001), found that the residency requirements pass intermediate scrutiny. In Nguyen, the Supreme Court upheld a requirement that U.S. citizen fathers take affirmative steps (i.e., legitimation; a declaration of paternity under oath by the father; or a court order of paternity) in order for a child to acquire citizenship, even though U.S. citizen mothers are not required to take such steps.
The Supreme Court granted the petition for certiorari to address the following question: “Whether the Court’s decision in Nguyen v. INS, 533 U.S. 53 (2001), permits gender discrimination that has no biological basis?” After argument, the Court issued a per curiam opinion  stating that “The judgment is affirmed by an equally divided Court.” Justice Kagan took no part in the consideration of the case.