The operation of venereal factors in human cervical cancer is suggested by demographic and epidemiological data. Recent evidence supporting the genital herpesvirus hypothesis is consistent with this notion. A controlled epidemiological investigation has been undertaken on the role of the male coital partner in cervical carcinogenesis. An answer is sought to the question, "Is the risk of developing cervical cancer increased among the wives of men who at some other time were married to other women who developed cervical cancer?" With one-quarter of the study completed, a total of 14 marital clusters have been identified in which 2 or more wives of the same men developed cervical carcinoma. The expected number of such clusters is estimated to be 4.