The genital human papillomavirus (HPV) is directly associated with cervical cancer, the second most common form of cancer among women. The study was guided by a synergistic interaction model of HPV risk factors. The relative risk of selected risk factors and cofactors associated with genital HPV infections was identified. Women at highest risk for acquiring an HPV infection had (a) initiated sex before age 15, (b) more than four lifetime sex partners, (c) more than one "once only" sexual partner, and (d) chosen male sex partners who previously had > 16 other female sex partners. Cofactors that increased risk by possibly contributing to progression of genital HPV infection were initiating oral contraceptive use before age 15 and having acquired more than three other sexually transmitted diseases. Past and current smokers were at a slightly higher risk compared to nonsmokers. Although other studies have identified risk factors, few have identified the relative risk of these factors.