There are distinct differences in the U.S. Food and Drug Administration's (FDA) licensing for the 2 HPV vaccines currently available. The quadrivalent vaccine (HPV4 [Gardasil, Merck & Co., North Wales, Pennsylvania]) protects against types 6, 11, 16, and 18, and is FDA-approved for both females and males aged 9 to 26 years (9). The bivalent vaccine (HPV2 [Cevarix, GlaxoSmithKline, Research Triangle Park, North Carolina]) protects against types 16 and 18 but is FDA-approved only for females (10). Both vaccines prevent cervical cancer; however, only HPV4 is FDA-approved for prevention of vulvar, vaginal, and anal cancer. Efficacy of the HPV4 vaccine for anal intraepithelial neoplasia in MSM ranges from 50% to 78% (11). Only HPV4 protects against genital warts. Although the rationale for protection is certainly plausible, clinical HPV vaccine data are not available for oropharyngeal cancer, recurrent respiratory papillomatosis, or penile cancer (9 - 10).