Scalia, J., concurring
SUPREME COURT OF THE UNITED STATES
 No. 99-2071
 TUAN ANH NGUYEN and JOSEPH BOULAIS,
PETITIONERS v. IMMIGRATION AND
NATURALIZATION SERVICE
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE FIFTH CIRCUIT
[June 11, 2001]
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 suit­namely, 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
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.

O'Connor, J., dissenting
SUPREME COURT OF THE UNITED STATES
 No. 99-2071
 TUAN ANH NGUYEN and JOSEPH BOULAIS,
PETITIONERS v. IMMIGRATION AND
NATURALIZATION SERVICE
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE FIFTH CIRCUIT
[June 11, 2001]
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
objectives­I 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. Feenstra, 450 U.S. 455, 461
(1981)); see also United States v. Virginia, 518 U.S. 515, 531 (1996). The defender of the
classification meets this burden "only 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.' " Mississippi Univ. for
Women, supra, at 724 (quoting Wengler v. Druggists Mut. Ins. Co., 446 U.S. 142, 150
(1980)); see also Virginia, supra, at 533.
Our cases provide significant guidance concerning the meaning of this standard and how
a reviewing court is to apply it. This Court's instruction concerning the application of
heightened scrutiny to sex-based classifications stands in stark contrast to our elucidation
of the rudiments of rational basis review. To begin with, under heightened scrutiny, "[t]he
burden of justification is demanding and it rests entirely on [the party defending the
classification]." Virginia, supra, at 533. Under rational basis scrutiny, by contrast, the
defender of the classification "has no obligation to produce evidence to sustain the

SUPREME COURT OF THE UNITED STATES
 No. 99-2071
 TUAN ANH NGUYEN and JOSEPH BOULAIS,
PETITIONERS v. IMMIGRATION AND
NATURALIZATION SERVICE
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE FIFTH CIRCUIT
[June 11, 2001]
Justice Kennedy delivered the opinion of the Court.
This case presents a question not resolved by a majority of the Court in a case before us
three Terms ago. See Miller v. Albright, 523 U.S. 420 (1998). Title §8 U.S.C.  1409
governs the acquisition of United States citizenship by persons born to one United States
citizen parent and one noncitizen parent when the parents are unmarried and the child is
born outside of the United States or its possessions. The statute imposes different
requirements for the child's acquisition of citizenship depending upon whether the citizen
parent is the mother or the father. The question before us is whether the statutory
distinction is consistent with the equal protection guarantee embedded in the Due Process
Clause of the Fifth Amendment.
I Petitioner Tuan Ahn Nguyen was born in Saigon, Vietnam, on September 11, 1969, to
copetitioner Joseph Boulais and a Vietnamese citizen. Boulais and Nguyen's mother were
not married. Boulais always has been a citizen of the United States, and he was in
Vietnam under the employ of a corporation. After he and Nguyen's mother ended their
relationship, Nguyen lived for a time with the family of Boulais' new Vietnamese
girlfriend. In June 1975, Nguyen, then almost six years of age, came to the United States.
He became a lawful permanent resident and was raised in Texas by Boulais.
In 1992, when Nguyen was 22, he pleaded guilty in a Texas state court to two counts of
sexual assault on a child. He was sentenced to eight years in prison on each count. Three
years later, the United States Immigration and Naturalization Service (INS) initiated
deportation proceedings against Nguyen as an alien who had been convicted of two
crimes involving moral turpitude, as well as an aggravated felony. See §8 U.S.C.  1227
(a)(2)(A)(ii) and (iii) (1994 ed., Supp. IV). Though later he would change his position
and argue he was a United States citizen, Nguyen testified at his deportation hearing that
he was a citizen of Vietnam. The Immigration Judge found him deportable.
Nguyen appealed to the Board of Immigration of Appeals and, in 1998, while the matter
was pending, his father obtained an order of parentage from a state court, based on DNA
testing. By this time, Nguyen was 28 years old. The Board dismissed Nguyen's appeal,
rejecting his claim to United States citizenship because he had failed to establish
compliance with §8 U.S.C.  1409 (a), which sets forth the requirements for one who was
born out of wedlock and abroad to a citizen father and a noncitizen mother.
Nguyen and Boulais appealed to the Court of Appeals for the Fifth Circuit, arguing that
§1409 violates equal protection by providing different rules for attainment of citizenship
by children born abroad and out of wedlock depending upon whether the one parent with

SUPREME COURT OF THE UNITED STATES
TUAN ANH NGUYEN et al. v. IMMIGRATION AND NATURALIZATION SERVICE
CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FIFTH
CIRCUIT
 No. 99-2071. Argued January 9, 2001­Decided June 11, 2001
 Petitioner Tuan Anh Nguyen was born out of wedlock in Vietnam to a Vietnamese
citizen and copetitioner Joseph Boulais, a United States citizen. Nguyen became a lawful
permanent United States resident at age six and was raised by Boulais. At age 22,
Nguyen pleaded guilty in a Texas state court to two counts of sexual assault on a child.
Subsequently, respondent Immigration and Naturalization Service initiated deportation
proceedings against him based on his serious criminal offenses. The Immigration Judge
ordered him deportable. Boulais obtained an order of parentage from a state court while
Nguyen's appeal was pending before the Board of Immigration Appeals, but the Board
dismissed the appeal, rejecting Nguyen's citizenship claim because he had not complied
with §8 U.S.C.  1409 (a)'s requirements for one born out of wedlock and abroad to a
citizen father and a noncitizen mother. On appeal, the Fifth Circuit rejected petitioners'
claim that §1409 violates equal protection by providing different citizenship rules for
children born abroad and out of wedlock depending on whether the citizen parent is the
mother or the father.
Held: Section 1409 is consistent with the equal protection guarantee embedded in the
Fifth Amendment's Due Process Clause. Pp. 3-18.
(a) A child born abroad and out of wedlock acquires at birth the nationality status of a
citizen mother who meets a specified residency requirement. §1409(c). However, when
the father is the citizen parent, inter alia, one of three affirmative steps must be taken
before the child turns 18: legitimization, a declaration of paternity under oath by the
father, or a court order of paternity. §1409(a)(4). The failure to satisfy this section renders
Nguyen ineligible for citizenship. Pp. 3-5.
(b) A gender-based classification withstands equal protection scrutiny if it serves
important governmental objectives and the discriminatory means employed are
substantially related to the achievement of those objectives. United States v. Virginia,
518 U.S. 515, 533. Congress' decision to impose different requirements on unmarried
fathers and unmarried mothers is based on the significant difference between their
respective relationships to the potential citizen at the time of birth and is justified by two
important governmental interests. Pp. 5-16.
(1) The first such interest is the importance of assuring that a biological parent-child
relationship exists. The mother's relation is verifiable from the birth itself and is
documented by the birth certificate or hospital records and the witnesses to the birth.
However, a father need not be present at the birth, and his presence is not incontrovertible
proof of fatherhood. See Lehr v. Robertson, 463 U.S. 248, 260, n. 16. Because fathers
and mothers are not similarly situated with regard to proof of biological parenthood, the
imposition of different rules for each is neither surprising nor troublesome from a
constitutional perspective. Section 1409(a)(4)'s provision of three options is designed to
ensure acceptable documentation of paternity. Petitioners argue that §1409(a)(1)'s
requirement that a father provide clear and convincing evidence of parentage is sufficient