Anorectal cancer and homosexuality.
D001005:Anus Neoplasms / Q000209:etiology* / Q000276:immunology; D006716:Homosexuality; D006801:Humans; D008297:Male; D012004:Rectal Neoplasms / Q000209:etiology* / Q000276:immunology; D012661:Semen / Q000276:immunology