The developing organism is particularly sensitive to exposure to estrogenic chemicals during a critical period in the induction of longterm changes in female reproductive organs, and persistent molecular alterations induced by the perinatal estrogenic agents. The perinatal mouse model can be utilized as an indicator of possible longterm consequences of exposure to exogenous estrogenic compounds including environmental endocrine disruptors. Attention should be paid to abnormalities in female genital organs exposed to estrogenic endocrine disruptors during fetal and early postnatal development in mammals including humans.