This study by Wyrobeak and Bruce investigates the effects of 25 chemicals on sperm abnormalities in (C57BL × C3H)F1 mice. The chemicals were administered subacutely at various dose levels over five consecutive days, and sperm abnormalities were assessed 1, 4, and 10 weeks later. The results show that 19 out of the 25 chemicals induced significant increases in sperm abnormalities, with methyl methanesulfonate, ethyl methanesulfonate, gilretholvin, benzo[a]pyrene, METEPA, tris(2-methyl-1-aziridinyl)phosphine oxide, THIOTEPA, mitomycin C, myleran, vinblastine sulphate, hydroxyurea, 3-methylcholanthrene, colchicine, actinomycin D, imuran, cyclophosphamide, 5-iododeoxyuridine, dichlorvos, aminopterin, and trimethylphosphate causing elevated levels of abnormal sperm. In contrast, dimethylnitrosamine, urethane, DDT, 1,1-dimethylhydrazine, caffeine, and calcium cyclamate did not induce significant sperm abnormalities. The study suggests that the chemicals tested may be mutagenic, teratogenic, or carcinogenic, and highlights the potential value of measuring sperm abnormalities as a rapid and reproducible method for screening chemicals for these properties.This study by Wyrobeak and Bruce investigates the effects of 25 chemicals on sperm abnormalities in (C57BL × C3H)F1 mice. The chemicals were administered subacutely at various dose levels over five consecutive days, and sperm abnormalities were assessed 1, 4, and 10 weeks later. The results show that 19 out of the 25 chemicals induced significant increases in sperm abnormalities, with methyl methanesulfonate, ethyl methanesulfonate, gilretholvin, benzo[a]pyrene, METEPA, tris(2-methyl-1-aziridinyl)phosphine oxide, THIOTEPA, mitomycin C, myleran, vinblastine sulphate, hydroxyurea, 3-methylcholanthrene, colchicine, actinomycin D, imuran, cyclophosphamide, 5-iododeoxyuridine, dichlorvos, aminopterin, and trimethylphosphate causing elevated levels of abnormal sperm. In contrast, dimethylnitrosamine, urethane, DDT, 1,1-dimethylhydrazine, caffeine, and calcium cyclamate did not induce significant sperm abnormalities. The study suggests that the chemicals tested may be mutagenic, teratogenic, or carcinogenic, and highlights the potential value of measuring sperm abnormalities as a rapid and reproducible method for screening chemicals for these properties.