From 1975 to the mid 1990s, the incidence of cancer in the oral cavity and pharynx (OC/P) declined substantively, in large part because of successful educational and medical campaigns to reduce cigarette smoking and tobacco chewing. Recent data, however, suggest that the incidence trend in young adults has reversed. The current study investigated National Cancer Institute Surveillance, Epidemiology and End Results databases for changes in the incidence of and survival from OC/P cancer. Since the mid 1990s, females in the United States, between 10 and 40 years of age, have had a steady, apparently accelerating, increase in the incidence of these cancers, particularly in females 15-34 years of age. Most of the increase occurred in the salivary glands and tongue, and were of squamous, acinar, and mucoepidermoid morphologic types. All racial/ethnic groups evaluated have shown the incidence trend pattern, with the increase most prominent in non-Hispanic whites. Five-year survival rates for females 15-39 years of age, when diagnosed to have OC/P cancer, show no improvement since 1975. In contrast, older females and males of all ages continue to demonstrate a reduction in incidence and improvement in survival. The observed patterns are consistent with changing sexual mores and increasing orogenital sexual practices in the United States, with transmission of human papillomavirus and potentially other sexually transmitted carcinogenic vectors. If so, the human papillomavirus vaccines will have cancer prevention benefits beyond cervical carcinoma and will be needed increasingly as the incidence of head and neck cancer is projected to continue to rise in young women. © 2009 Elsevier Inc. All rights reserved.