P has been infected with HIV since 1986. Her infection had not manifested its most serious symptoms. On September 16, 1994, she went to D’s office for a dental appointment. She disclosed her HIV infection on the patient registration form. D completed a dental examination, discovered a cavity, and informed P 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, but P would be responsible for the cost of using the hospital's facilities. D declined. P sued D 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). '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 District Court ruled in favor of P. The court held that D failed to raise a genuine issue of material fact as to whether P’s infection would have posed a direct threat to the health or safety of others during the course of a dental treatment. The Court of Appeals affirmed relying 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. D appealed.