Genital warts or venereal warts is a highly contagious sexually transmitted infection caused by some sub-types of human papilloma virus (HPV). It is spread through direct skin-to-skin contact during oral, genital, or anal sex with an infected partner. Genital warts are the most easily recognized sign of genital HPV infection. They can be caused by strains of genital HPV; types 6 and 11 are responsible for 90% of genital warts cases. Most people who acquire those strains never develop warts or any other symptoms. HPV also causes many cases of cervical cancer; types 16 and 18 account for 70% of cases.