Numerous reports on colon carcinogenesis reveal gender differences in the incidence and location of tumors. A large number of the presented studies suggest that sex-steroids have a considerable effect on tumorigenesis of the large bowel. To clarify the, so far, not fully understood mechanisms and somewhat conflicting information about the possible hormone action, it is important to discuss two points: first, the reliability of the currently used experimental animal models; and second, what is known concerning the role of sex steroids in colon carcinogenesis.