The causes of cervical cancer are particularly associated with human papillomavirus (HPV) infection. The primary causes that can lead to precancerous lesions and cervical cancer itself, in a minority of cases, do not detect HPV DNA, especially in older patients. Epidemiological studies show that early childbirth and multiple childbirths are highly related to the incidence of cervical cancer; as the number of childbirths increases, the risk of cervical cancer also increases. Smoking can suppress the body's immune function and may promote cancer development. Men who have had penile cancer, prostate cancer, or previous cervical cancer are at high risk; therefore, women who have contact with high-risk men are also more susceptible to cervical cancer.