While Gu et al. [4] reported only one polydactyly in a total of 1481 control and irradiated ICR embryos, polydactyly was by far the most frequent malformation found in the first generation fetuses issued from control or X-irradiated ICR females. In contrast to the study by Gu et al. [4], we also considered dwarfism as a potential anomaly resulting from irradiation of one-cell embryos. Indeed, dwarfism causes a severe or lethal handicap after birth and is often associated with visible malformations of the fetus. In man, LBW (low birth weight), defined by WHO as a birth weight of less than 2500 g, is probably the single most important factor that affects infant mortality and morbidity [16].