The relevance of preconceptional and prenatal toxicant exposures for
genomic stability in offspring is difficult to analyze in human populations, because gestational exposures usually cannot be separated from preconceptional exposures. To analyze the roles of exposures during gestation and conception on
genomic stability in the offspring, stability was assessed via the Comet assay and highly sensitive, semiautomated confocal
laser scans of γH2AX foci in cord, maternal, and paternal blood as well as spermatozoa from 39 families in Crete, Greece, and the United Kingdom. With use of multivariate linear regression analysis with backward selection, preconceptional paternal smoking (% tail
DNA: P>0.032; γH2AX foci: P>0.018) and gestational maternal (% tail
DNA: P>0.033) smoking were found to statistically significantly predict DNA damage in the cord blood of F1 offspring. Maternal passive
smoke exposure was not identified as a predictor of DNA damage in cord blood, indicating that the effect of paternal smoking may be transmitted via the spermatozoal genome. Taken together, these studies reveal a role for cigarette
smoke in the induction of
DNA alterations in human F1 offspring via exposures of the fetus in utero or the paternal germline. Moreover, the identification of transgenerational
DNA alterations in the unexposed F1 offspring of smoking-exposed fathers supports the claim that cigarette
smoke is a human germ cell
mutagen.