General overview of studies of multigeneration carcinogenesis in man, particularly in relation to exposure to chemicals.

This overview is concerned mainly with possible effects on the offspring of individuals exposed preconceptually to therapeutic drugs and radiotherapy. The studies reported so far give no evidence for transgenerational carcinogenesis by these agents; however, the length of follow-up of the offspring has often been short and the numbers of offspring studied too small to detect even important risks. Similarly, there is no evidence of transgenerational carcinogenesis in other groups exposed to potential mutagens. (Transgenerational effects of radiation other than radiotherapy, and transplacental effects, are discussed by other contributors.) Suggestions are given for groups which might be included in cohort studies, and estimates made of the numbers required for such studies. Any such study should include other indicators of genotoxic damage as well as cancer; this is likely to increase the scientific interest and value of the study and to make it more relevant to wider concerns about environmental mutagens.