Reassessment of models used to test xenobiotics for oestrogenic potency is overdue.

Product safety bioassays need to include data from animals with susceptible genotypes or the potential for environmental compounds to disrupt reproductive development in hormonally sensitive populations may be greatly underestimated. The continued use of resistant animal models is likely to result in allowable releases of toxic levels of oestrogenic agents that could differentially disrupt reproductive development and function of sensitive genotypes, leading to reproductive failure and loss or extinction of susceptible individuals, populations and species. Rather than ignoring the role of genetic differences in susceptibility to oestrogenic agent-induced carcinogenicity and endocrine disruption, government agencies should support efforts to identify the genetic mechanisms involved in these responses, and to screen for and develop strains of mice and rats which are sensitive to the induction of genotoxicity/carcinogenicity as well as the inhibition of reproductive development and function by oestrogenic agents. Such sensitive strains would be even more optimal for testing chemicals for endocrine disruptor activity.