E nacted over three decades ago, Title IX of the Education Amendments of 1972 prohibits discrimination on the basis of sex in federally funded education programs or activities. Although Title IX bars recipients of federal financial assistance from discriminating on the basis of sex in a wide range of educational programs or activities, both the statute and the implementing regulations have long permitted school districts to operate single-sex schools. In 2006, however, the Department of Education (ED) issued Title IX regulations that, for the first time, authorized schools to operate individual classes on a single-sex basis. The issuance of these regulations has raised a number of legal questions regarding whether single-sex classrooms pose constitutional problems under the equal protection clause or conflict with statutory requirements under Title IX or under the Equal Educational Opportunities Act (EEOA). Under Title IX, "No person ... shall, on the basis of sex, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any education program or activity receiving Federal financial assistance." Although the statute prohibits a broad range of discriminatory actions, such as bias in college sports and sexual harassment in schools, Title IX does contain several exceptions. One of these exceptions provides that, with respect to admissions, Title IX applies only to institutions of vocational education, professional education, and graduate higher education, and to public institutions of undergraduate higher education, unless the latter has traditionally admitted students of only one sex. As a result, Title IX does not apply to admissions to nonvocational elementary or secondary schools, nor does it apply to certain institutions of undergraduate higher education. This means that Title IX permits public or private single-sex elementary and secondary schools, as well as some single-sex colleges. This exception for single-sex schools has existed since the legislation was enacted, and "the legislative history indicates that Congress excepted elementary and secondary schools from Title IX because of the potential benefits of single-sex education." Less clear is whether Congress intended to permit coeducational schools to establish individual classes on a single-sex basis, as ED's regulations now allow. Noting that some studies demonstrate that students learn better in a single-sex educational environment, ED issued new Title IX regulations in 2006 that provide recipients of educational funding with additional flexibility in providing single-sex classes. The regulations apply to both public and private elementary and secondary schools but not to vocational schools. Specifically, the regulations permit recipients to offer single-sex classes and extracurricular activities "if (1) the purpose of the class or extracurricular activity is achievement of an important governmental or educational objective, and (2) the single-sex nature of the class or extracurricular activity is substantially related to achievement of that objective." In its regulations, ED identified two objectives that would meet the first requirement: (1) to provide a diversity of educational options to parents and students, and (2) to meet the particular, identified educational needs of students. According to the regulations, any schools that choose to provide single-sex classes must meet certain requirements designed to ensure nondiscrimination. For example, participation in single-sex classes must be completely voluntary, recipients must treat male and female students in an "evenhanded" manner, and a recipient's justification must be genuine. These latter requirements mean than a school's use of overly broad sex-based generalizations in connection with offering single-sex education would be sex discrimination. Thus, recipients are prohibited from providing single-sex classes on the basis of generalizations about the different talents, capacities, or preferences of either sex. In addition, although schools must always provide a "substantially equal" coeducational class in the same subject, they are not always required to provide single-sex classes for the excluded sex, unless such classes would be required to ensure nondiscriminatory implementation. If recipients can show that students of the excluded sex are not interested in enrolling in a single-sex class or do not have educational needs that can be addressed by such a class, then they are not required to offer a corresponding single-sex class to the excluded sex. Although schools must offer classes that are substantially equal, these classes do not have to be identical. In comparing classes under the "substantially equal" requirement, ED will consider a range of factors, including, but not limited to, admissions policies; the educational benefits provided, including the quality, range, and content of curriculum and other services, and the quality and availability of books, instructional materials, and technology; the qualifications of faculty and staff; the quality, accessibility, and availability of facilities and resources; geographic accessibility; and intangible features, such as the reputation of the faculty. In order to ensure compliance with the regulations, recipients are required to periodically conduct self-evaluations, and students or their parents who believe the regulations have been violated may file a complaint with the school or with ED. ED also has the authority to conduct periodic compliance reviews. According to the National Association for Single Sex Public Education, there are currently at least 514 public schools in the United States that offer single-sex education in the form of single-sex schools or classrooms. As noted above, the enactment of the new regulations raises questions regarding whether ED has the statutory authority under Title IX to authorize single-sex classrooms and whether the regulations comply with the statutory requirements of the EEOA. Although Title IX explicitly authorizes single-sex schools, the statute is silent with respect to the question of single-sex classrooms within schools that are otherwise coeducational. As a result, it is possible that the regulations could face a legal challenge on the grounds that ED exceeded its statutory authority. Any court ruling as to the validity of ED's regulations would hinge on the level of deference paid to the agency decision by the reviewing court. The standard for judicial review of such agency action was delineated in Chevron U.S.A. Inc. v. Natural Resources Defense Council . There, the Supreme Court established that judicial review of an agency's interpretation of a statute consists of two related questions. First, the court must determine whether Congress has spoken directly to the precise issue at hand. If the intent of Congress is clear, the inquiry is concluded, since the unambiguously expressed intent of Congress must be respected. However, if the court determines that the statute is silent or ambiguous with respect to the specific issue at hand, the court must determine "whether the agency's answer is based on a permissible construction of the statute." It is important to note that the second prong does not require a court to "conclude that the agency construction was the only one it permissibly could have adopted to uphold the construction, or even the reading the court would have reached if the question initially had arisen in a judicial proceeding." The practical effect of this maxim is that a reasonable agency interpretation of an ambiguous statute must be accorded deference, even if the court believes the agency is incorrect. Ultimately, given Title IX's silence with respect to single-sex classrooms, it's possible, but not certain, that a court could determine that the statutory language was ambiguous enough to support ED's interpretation of the statute. Although the EEOA contains a congressional finding that "the maintenance of dual school systems in which students are assigned to schools solely on the basis of race, color, sex, or national origin denies to those students the equal protection of the laws guaranteed by the fourteenth amendment," the statute's prohibition against "the deliberate segregation" of students applies only to segregation on the basis of race, color, or national origin, but not sex. Therefore, ED's regulations regarding single-sex classrooms do not appear to conflict with the EEOA. Over the years, several courts have considered the question of whether single-sex education violates the EEOA. Although these cases, which are few in number, have contemplated single-sex schools rather than single-sex classes, they are instructive. For example, in Vorchheimer v. School District of Philadelphia , the Court of Appeals for the Third Circuit considered a challenge filed by a female student who was denied admission to an all-male public high school in Philadelphia. Because the statute did not explicitly prohibit the segregation of schools by sex and because the corresponding all-female high school was found to provide equal educational opportunities for girls, the court rejected the EEOA challenge. In United States v. Hinds County School Board , however, the Fifth Circuit held that the EEOA prohibited a Mississippi school district from splitting the four schools in the district into two all-male schools and two-all female schools. The court distinguished the case from the Vorchheimer decision, noting that Vorchheimer involved two voluntary single-sex schools in an otherwise coeducational school system while the Mississippi school district in question involved the mandatory sex segregation of all of the schools, and therefore all of the students, in the system. Read together, these cases indicate that the EEOA may permit single-sex schools as long as coeducational options are available. Such an interpretation would mean that the new Title IX regulatory requirements are consistent with the EEOA. As noted above, the 2006 Title IX regulations may raise constitutional issues for public schools that offer single-sex classes. Under the equal protection clause of the Fourteenth Amendment, which prohibits the government from denying to any individual the equal protection of the law, governmental classifications that are based on sex receive heightened scrutiny from the courts. Laws that rely on sex-based classifications will survive such scrutiny only if they are substantially related to achieving an important government objective. Currently, there are only two Supreme Court cases that address the equal protection implications of sex-segregated schools. Although both of these cases occurred in a higher education setting, they provide some guidance that may be applicable to the elementary and secondary education context. In the earlier case, Mississippi University for Women v. Hogan , the Court held that the exclusion of an individual from a publicly funded school because of his or her sex violates the equal protection clause unless the government can show that the sex-based classification serves important governmental objectives and that the discriminatory means employed are substantially related to the achievement of those objectives.