There is evidence that sex hormones and intrauterine factors are involved in the etiology of testicular cancer. We evaluated the importance of perinatal and adult life correlates of sex hormones as risk factors for testicular cancer in a case control study of 97 incident, histologically confirmed cases, residents of the Greater Athens area and environs, who were diagnosed in the 3 specialized cancer hospitals and the major General Hospital in Athens during the 2 year period 1993-94. Cases were age-matched to 2 healthy controls from the same study base. Both cases and controls as well as their mothers were interviewed by the same investigator and the data were analyzed through conditional logistic regression. The odds ratio for testicular cancer was elevated among persons born after a pregnancy characterized by severe nausea. Among the adult life factors, higher body mass was associated with reduced risk, as was evidence of baldness. To the extent that nausea during pregnancy reflects higher levels of pregnancy estrogens on the one hand, and baldness is linked to androgens on the other, our data suggest that estrogens in the intrauterine life and androgens at later stages may have sequential opposing effects for the development of testicular cancer.