Opinion of the Court

Even if one conceives of the interest Congress pursues as the establishment of a real, practical relationship of considerable substance between parent and child in every case, as opposed simply to ensuring the potential for the relationship to begin, petitioners' misconception of the nature of the equal protection inquiry is fatal to their argument. A statute meets the equal protection standard we here apply so long as it is """substantially related to the achievement of""" the governmental objective in question. Virginia, supra, at 533 (quoting Hogan, 458 U. S., at 724, in turn quoting Wengler, 446 U. S., at 150). It is almost axiomatic that a policy which seeks to foster the opportunity for meaningful parent-child bonds to develop has a close and substantial bearing on the governmental interest in the actual formation of that bond. None of our gender-based classification equal protection cases have required that the statute under consideration must be capable of achieving its ultimate objective in every instance. In this difficult context of conferring citizenship on vast numbers of persons, the means adopted by Congress are in substantial furtherance of important governmental objectives. The fit between the means and the important end is “exceedingly persuasive." See Virginia, supra, at 533. We have explained that an “exceedingly persuasive justification" is established "by showing at least that the classification serves 'important governmental objectives and that the discriminatory means employed' are 'substantially related to the achievement of those objectives." Hogan, supra, at 724 (citations omitted). Section 1409 meets this standard.

C

In analyzing § 1409(a)(4), we are mindful that the obligation it imposes with respect to the acquisition of citizenship by the child of a citizen father is minimal. This circumstance shows that Congress has not erected inordinate and unnecessary hurdles to the conferral of citizenship on the

Opinion of the Court

children of citizen fathers in furthering its important objectives. Only the least onerous of the three options provided for in § 1409(a)(4) must be satisfied. If the child has been legitimated under the law of the relevant jurisdiction, that will be the end of the matter. See § 1409(a)(4)(A). In the alternative, a father who has not legitimated his child by formal means need only make a written acknowledgment of paternity under oath in order to transmit citizenship to his child, hardly a substantial burden. See § 1409(a)(4)(B). Or, the father could choose to obtain a court order of paternity. See § 1409(a)(4)(C). The statute can be satisfied on the day of birth, or the next day, or for the next 18 years. In this case, the unfortunate, even tragic, circumstance is that Boulais did not pursue, or perhaps did not know of, these simple steps and alternatives. Any omission, however, does not nullify the statutory scheme.

Section 1409(a), moreover, is not the sole means by which the child of a citizen father can attain citizenship. An individual who fails to comply with § 1409(a), but who has substantial ties to the United States, can seek citizenship in his or her own right, rather than via reliance on ties to a citizen parent. See, e. g., 8 U. S. C. §§ 1423, 1427. This option now may be foreclosed to Nguyen, but any bar is due to the serious nature of his criminal offenses, not to an equal protection denial or to any supposed rigidity or harshness in the citizenship laws.

IV

The statutory scheme's satisfaction of the equal protection scrutiny we apply to gender-based classifications constitutes a sufficient basis for upholding it. It should be noted, however, that, even were we to conclude that the statute did not meet this standard of review, petitioners would face additional obstacles before they could prevail.

The INS urges that, irrespective of whether § 1409(a) is constitutional, the Court cannot grant the relief petitioners request: the conferral of citizenship on terms other than

Opinion of the Court

those specified by Congress. There may well be "potential problems with fashioning a remedy" were we to find the statute unconstitutional. See Miller, 523 U. S., at 451 (O'CONNOR, J., concurring in judgment); cf. id., at 445, n. 26 (opinion of STEVENS, J.) (declining to address the question whether the Court could confer the sought-after remedy). Two Members of today's majority said in Miller that this argument was dispositive. See id., at 452-459 (SCALIA, J., joined by THOMAS, J., concurring in judgment). Petitioners ask us to invalidate and sever §§ 1409(a)(3) and (a)(4), but it must be remembered that severance is based on the assumption that Congress would have intended the result. See id., at 457 (SCALIA, J., concurring in judgment) (citing New York v. United States, 505 U. S. 144 (1992)). In this regard, it is significant that, although the Immigration and Nationality Act contains a general severability provision, Congress expressly provided with respect to the very subchapter of the United States Code at issue and in a provision entitled "Sole procedure" that "[a] person may only be naturalized as a citizen of the United States in the manner and under the conditions prescribed in this subchapter and not otherwise." 8 U. S. C. § 1421(d); see also Miller, supra, at 457-458 (SCALIA, J., concurring in judgment). Section 1421(d) refers to naturalization, which in turn is defined as “conferring of nationality of a state upon a person after birth.” 8 U. S. C. § 1101(a)(23). Citizenship under § 1409(a) is retroactive to the date of birth, but it is a naturalization under § 1421(d) nevertheless. The conditions specified by § 1409(a) for conferral of citizenship, as a matter of definition, must take place after the child is born, in some instances taking as long as 18 years. Section 1409(a), then, is subject to the limitation imposed by § 1421(d).

In light of our holding that there is no equal protection violation, we need not rely on this argument. For the same reason, we need not assess the implications of statements in our earlier cases regarding the wide deference afforded to

SCALIA, J., concurring

Congress in the exercise of its immigration and naturalization power. See, e. g., Fiallo v. Bell, 430 U. S. 787, 792–793, and n. 4 (1977) (quoting Galvan v. Press, 347 U. S. 522, 531 (1954)); 430 U. S., at 792 (quoting Oceanic Steam Nav. Co. v. Stranahan, 214 U. S. 320, 339 (1909)). These arguments would have to be considered, however, were it to be determined that § 1409 did not withstand conventional equal protection scrutiny.

V

To fail to acknowledge even our most basic biological differences-such as the fact that a mother must be present at birth but the father need not be-risks making the guarantee of equal protection superficial, and so disserving it. Mechanistic classification of all our differences as stereotypes would operate to obscure those misconceptions and prejudices that are real. The distinction embodied in the statutory scheme here at issue is not marked by misconception and prejudice, nor does it show disrespect for either class. The difference between men and women in relation to the birth process is a real one, and the principle of equal protection does not forbid Congress to address the problem at hand in a manner specific to each gender. The judgment of the Court of Appeals is

Affirmed.

JUSTICE SCALIA, with whom JUSTICE THOMAS joins, concurring.

I remain of the view that the Court lacks power to provide relief of the sort requested in this suit-namely, conferral of citizenship on a basis other than that prescribed by Congress. See Miller v. Albright, 523 U. S. 420, 452 (1998) (SCALIA, J., concurring in judgment). A majority of the Justices in Miller having concluded otherwise, see id., at 423 (opinion of STEVENS, J., joined by REHNQUIST, C. J.); id., at 460 (GINSBURG, J., joined by SOUTER and BREYER, JJ., dissenting); id., at 471 (BREYER, J., joined by SOUTER and

O'CONNOR, J., dissenting

GINSBURG, JJ., dissenting); and a majority of the Court today proceeding on the same assumption; I think it appropriate for me to reach the merits of petitioners' equal protection claims. I join the opinion of the Court.

JUSTICE O'CONNOR, with whom JUSTICE SOUTER, JUSTICE GINSBURG, and JUSTICE BREYER join, dissenting.

In a long line of cases spanning nearly three decades, this Court has applied heightened scrutiny to legislative classifications based on sex. The Court today confronts another statute that classifies individuals on the basis of their sex. While the Court invokes heightened scrutiny, the manner in which it explains and applies this standard is a stranger to our precedents. Because the Immigration and Naturalization Service (INS) has not shown an exceedingly persuasive justification for the sex-based classification embodied in 8 U. S. C. § 1409(a)(4)—i. e., because it has failed to establish at least that the classification substantially relates to the achievement of important governmental objectives—I would reverse the judgment of the Court of Appeals.

I

Sex-based statutes, even when accurately reflecting the way most men or women behave, deny individuals opportunity. Such generalizations must be viewed not in isolation, but in the context of our Nation's "long and unfortunate history of sex discrimination."" J. E. B. v. Alabama ex rel. T. B., 511 U. S. 127, 136 (1994) (quoting Frontiero v. Richardson, 411 U. S. 677, 684 (1973) (plurality opinion)). Sex-based generalizations both reflect and reinforce "fixed notions concerning the roles and abilities of males and females." Mississippi Univ. for Women v. Hogan, 458 U. S. 718, 725 (1982).

For these reasons, a party who seeks to defend a statute that classifies individuals on the basis of sex "must carry the burden of showing an 'exceedingly persuasive justification' for the classification." Id., at 724 (quoting Kirchberg v.