Genital Human Papilloma Virus (HPV) infection is the most common sexually transmitted infection (STI) in the United States and worldwide. Over 50% of sexually active adolescents will become infected with HPV. HPV infection is strongly associated with the development of anogenital dysplasias and invasive cancers. Because HPV is a STI, optimal prevention in women will depend on prevention in their partners as well. Males remain a significant reservoir of HPV and vaccinating them will be essential for rapidly preventing transmission of HPV in the community.