Another mutagen known to produce cancer is urethane. When pregnant mice are treated with this chemical not only do they develop cancer of the lung but their young do, also. The only exposure of the infant mice to urethane was prenatal in these experiments, proving that the chemical must have passed through the placenta. In human populations exposed to urethane or related chemicals there is a possibility that tumors will develop in infants through prenatal exposure, as Dr. Hueper has warned.
