Dibenzo[def,p]chrysene (DBC) is a transplacental carcinogen in mice (15 mg/kg; gestation day (GD) 17). To mimic residual exposure throughout pregnancy, dams received 4 smaller doses of DBC (3.75 mg/kg) on GD 5, 9, 13 and 17. This regimen alleviated the previously established carcinogenic responses in the thymus, lung, and liver....