6 SESSIONS v. MORALES-SANTANA Opinion of the Court Republic. Record 253, 366; App. to Pet. for Cert. 45a–49a. In 2010, Morales-Santana moved to reopen the proceed­ ings, asserting that the Government’s refusal to recognize that he derived citizenship from his U. S.-citizen father violated the Constitution’s equal protection guarantee. See Record 27, 45. The Board of Immigration Appeals (BIA) denied the motion. App. to Pet. for Cert. 8a, 42a– 44a. The United States Court of Appeals for the Second Circuit reversed the BIA’s decision. 804 F. 3d 520, 524 (2015). Relying on this Court’s post-1970 construction of the equal protection principle as it bears on gender-based classifications, the court held unconstitutional the differ­ ential treatment of unwed mothers and fathers. Id., at 527–535. To cure the constitutional flaw, the court further held that Morales-Santana derived citizenship through his father, just as he would were his mother the U. S. citizen. Id., at 535–538. In so ruling, the Second Circuit declined to follow the conflicting decision of the Ninth Circuit in United States v. Flores-Villar, 536 F. 3d 990 (2008), see 804 F. 3d, at 530, 535, n. 17. We granted certiorari in Flores-Villar, but ultimately affirmed by an equally divided Court. Flores-Villar v. United States, 564 U. S. 210 (2011) ( per curiam). Taking up Morales-Santana’s request for review, 579 U. S. ___ (2016), we consider the matter anew. II Because §1409 treats sons and daughters alike, MoralesSantana does not suffer discrimination on the basis of his gender. He complains, instead, of gender-based discrimi­ nation against his father, who was unwed at the time of Morales-Santana’s birth and was not accorded the right an unwed U. S.-citizen mother would have to transmit citi­ zenship to her child. Although the Government does not contend otherwise, we briefly explain why Morales­