The Supreme Court has granted certiorari in a case challenging citizenship laws that treat the nonmarital children of US citizen mothers and fathers differently.  The case, Flores-Villar v. United States, 536 F.3d 990 (9th Cir. 2009) (Supreme Court docket no. 09-5801) poses an equal protection issue similar to the one in Nguyen v. I.N.S., 533 U.S. 53 (2001).  Nguyen concerned the nonmarital child of a U.S. citizen father and non-citizen mother whose paternity had never been legally established.   Flores-Villar centers on a statute imposing a residence requirement on citizen fathers before they can transmit citizenship to nonmarital children born abroad to a noncitizen mother.   The law that Mr. Flores-Villar is challenging was substantially revised (to shorten the residency period) for children born after 1986, but the statute still treats men and women differently.  See  8 U.S.C. 1401(g) and 1409(a) and (c). See also this short piece by Adam Liptak in the New York Times: Justices to Weigh Law on Gaining Citizenship Via Parents