They are often found on the vulva, in the vagina, on the cervix, inside and outside on the penis, and in and around the anus. Many are microscopic and invisible to the naked eye. This is why health care providers use an instrument called a colposcope to greatly magnify an area to see if any warts are present. There are at least 65 different strains of HPV that have been identified to date. Two of these, types 16 and 18, have been associated with cancer of the cervix, vagina, vulva, penis, and anus.
Some clinics can use DNA tests to type warts.
Most visible warts are caused by types 6 and 11 and are not associated with precancerous lesions or cancer. You, and many other students, have asked about the possibility of transmission of genital warts during oral sex. Yes, it could be possible to pass on this virus during oral sex, whether or not warts are present. For some reason, HPV prefers genital and anal skin.