A Study to Compare Immune Response of V503 to Gardasil in 16- to 26-year-old Men (V503-020)

Inclusion Criteria:

* Subject is a man, between the ages of 16 years and 0 days and 26 years and 364 days on the day of enrolment.
* Subject is a man who has had no more than 5 lifetime female sexual partners.
* Subject is judged to be in good physical health on the basis of medical history, physical examination, and laboratory results.
* Subject, or subject's parent or guardian, fully understand study procedures, alternative treatments available, the risks involved with the study, and voluntarily agree to participate by giving written informed consent.

Exclusion Criteria:

* Subject who has had sex with a male partner.
* Subject has a history of HPV-related external genital lesions or HPV-related anal lesions
* Subject has a known allergy to any vaccine component, including aluminium, yeast, or BENZONASE
* Subject has a history of severe allergic reaction that required medical intervention.
* Subject has thrombocytopenia or any coagulation disorder that would contraindicate intramuscular injections.
* Subject is concurrently enrolled in clinical studies of investigational medicinal products.
* Subject has donated blood within 1 week prior to the Day 1 vaccination, or intends to donate during Day 1 through Month 7 of the study.
* Subject is currently immunocompromised or has been diagnosed as having a congenital or acquired immunodeficiency, HIV infection, lymphoma, leukemia, systemic lupus erythematosus, rheumatoid arthritis, juvenile rheumatoid arthritis, inflammatory bowel disease, or other autoimmune condition.
* Subject has had a splenectomy.
* Subject is receiving or has received in the year prior to enrolment the following immunosuppressive therapies: radiation therapy, cyclophosphamide, azathioprine, methotrexate, any chemotherapy, cyclosporin, leflunomide, TNF-α antagonists, monoclonal antibody therapies, intravenous gamma globulin, antilymphocyte sera, or other therapy known to interfere with the immune response.
* Subject has received any immune globulin product or blood-derived product within the 6 months prior to the Day 1 vaccination, or plans to receive any such product during Day 1 through Month 7 of the study.
* Subject has received non-replicating (inactivated) vaccines within 14 days prior to the Day 1 vaccination or has received replicating (live) vaccines within 21 days prior to the Day 1 vaccination.
* Subject has received a marketed HPV vaccine, or has participated in an HPV vaccine clinical trial and has received either active agent or placebo.
* Subject has had a fever within the 24-hour period prior to the Day 1 vaccination.
* Subject has a history or current evidence of any condition, therapy, laboratory abnormality or other circumstance that might confound the results of the study, or interfere with the subject's participation for the full duration of the study, such that it is not in the best interest of the subject to participate.
* Subject is unlikely to adhere to the study procedures, keep appointments, or is planning to relocate during the study.
* Subject is, at the time of signing informed consent, a user of recreational or illicit drugs or has had a recent history (within the last year) of drug abuse or dependence. Alcohol abusers are defined as those who drink despite recurrent social, interpersonal, and/or legal problems as a result of alcohol use.
* Subject, or subject's parent or guardian, is or has an immediate family member (spouse or children) who is investigational site or sponsor staff directly involved with this trial.