Justice Kennedy delivered the opinion of the Court.
We address in this case the application of the Americans with Disabilities Act of 1990 (ADA), 104 Stat. 327, 42 U.S.C. §12101 et seq., to persons infected with the human immunodeficiency virus (HIV). We granted certiorari to review, first, whether HIV infection is a disability under the ADA when the infection has not yet progressed to the so-called symptomatic phase; and, second, whether the Court of Appeals, in affirming a grant of summary judgment, cited sufficient material in the record to determine, as a matter of law, that respondent's infection with HIV posed no direct threat to the health and safety of her treating dentist. 552 U.S. 991 (1997).
I
Respondent Sidney Abbott (hereinafter respondent) has been infected with HIV since 1986. When the incidents we recite occurred, her infection had not manifested its most serious symptoms. On September 16, 1994, she went to the office of petitioner Randon Bragdon in Bangor, Maine, for a dental appointment. She disclosed her HIV infection on the [p. 629] patient registration form. Petitioner completed a dental examination, discovered a cavity, and informed respondent of his policy against filling cavities of HIV-infected patients. He offered to perform the work at a hospital with no added fee for his services, though respondent would be responsible for the cost of using the hospital's facilities. Respondent declined.
Respondent sued petitioner under state law and §302 of the ADA, 104 Stat. 355, 42 U.S.C. §12182, alleging discrimination on the basis of her disability. The state-law claims are not before us. Section 302 of the ADA provides:
"No individual shall be discriminated against on the basis of disability in the full and equal enjoyment of the goods, services, facilities, privileges, advantages, or accommodations of any place of public accommodation by any person who…operates a place of public accommodation." §12182(a).
The term "public accommodation" is defined to include the "professional office of a health care provider." §12181(7)(F).
A later subsection qualifies the mandate not to discriminate. It provides:
"Nothing in this subchapter shall require an entity to permit an individual to participate in or benefit from the goods, services, facilities, privileges, advantages and accommodations of such entity where such individual poses a direct threat to the health or safety of others." §12182(b)(3).
The United States and the Maine Human Rights Commission intervened as plaintiffs. After discovery, the parties filed cross-motions for summary judgment. The District Court ruled in favor of the plaintiffs, holding that respondent's HIV infection satisfied the ADA's definition of disability. 912 F.Supp. 580, 585–587 (Me. 1995). The court held further that petitioner raised no genuine issue of material fact as to whether respondent's HIV infection would have [p. 630] posed a direct threat to the health or safety of others during the course of a dental treatment. Id., at 587–591. The court relied on affidavits submitted by Dr. Donald Wayne Marianos, Director of the Division of Oral Health of the Centers for Disease Control and Prevention (CDC). The Marianos affidavits asserted it is safe for dentists to treat patients infected with HIV in dental offices if the dentist follows the so-called universal precautions described in the Recommended Infection-Control Practices for Dentistry issued by CDC in 1993 (1993 CDC Dentistry Guidelines). 912 F.Supp., at 589.
The Court of Appeals affirmed. It held respondent's HIV infection was a disability under the ADA, even though her infection had not yet progressed to the symptomatic stage. 107 F.3d 934, 939–943 (CA1 1997). The Court of Appeals also agreed that treating the respondent in petitioner's office would not have posed a direct threat to the health and safety of others. Id., at 943–948. Unlike the District Court, however, the Court of Appeals declined to rely on the Marianos affidavits. Id., at 946, n. 7. Instead the court relied on the 1993 CDC Dentistry Guidelines, as well as the Policy on AIDS, HIV Infection and the Practice of Dentistry, promulgated by the American Dental Association in 1991 (1991 American Dental Association Policy on HIV). 107 F.3d, at 945–946.
II
We first review the ruling that respondent's HIV infection constituted a disability under the ADA. The statute defines disability as:
"(A) a physical or mental impairment that substantially limits one or more of the major life activities of such individual;
"(B) a record of such an impairment; or
"(C) being regarded as having such an impairment." §12102(2).