Sexual behavior has long been known to be a risk factor for cervical carcinoma. Certain sexual risk factors are related to an increased risk of chronic infection of the cervical transformation zone with high-risk human papilloma viruses (HPVs). Numerous retrospective analyses consider early first intercourse a probable risk factor for later development of cervical carcinoma. Since risk factors are associated, it is unclear whether early first intercourse is an independent risk factor for cervical neoplasia. Few comprehensive retrospective studies are available. It is possible that the cervical transformation zone is particularly vulnerable to infection between menarche and the age of sixteen. During this phase there are a large number of undifferentiated cells at the periphery of the metaplasia, practically at the surface of the cervix. It seems that this area is particularly susceptible to HPV infection. There are also indications that there is no secondary immune response to HPV at the time of early first intercourse, making the immune response to HPV less efficient. Other possible risk factors for cervical cancer include genetic predisposition, nutrition, smoking, Chlamydia or HSV-2 infections, drug abuse, oral contraception, immune suppression and early first pregnancy. Education appears important to encourage responsible sexual behaviour in young people.