“…Questions were included concerning five factors that were chosen as the most reliable and most important of those known to influence the prevalence rate of cervical carcinoma: age, ethnic origin, age at first pregnancy (as a reflection of early sexual experience), number of children born alive (as a reflection of the number of pregnancies), and net weekly family income (as a reflection of socioeconomic status) (Lombard and Potter, 1950;Wynder et al, 1954;Jones et al, 1958 ;Haenszel and Hillhouse, 1959;Terris and Oalmann, 1960;Rotkin, 1962;Rotkin and King, 1962;Boyd and Doll, 1964;Christopherson and Parker, 1965 …”