以环磷酰胺处理雄性小鼠后每周与超排卵雌鼠交配，制备分析受精卵染色体，持续整个生精周期（7周）。处理组小鼠雄原核染色体出现多种畸形，最敏感期在处理后第8天，相当于诱变剂作用于睾丸精子期。处理后第8天的小鼠精子体外受精试验表明，睾丸精子期受环磷酰胺作用后的精子其活力和密度未受显著影响，但其对卵子的受精能力降低，胚胎发育受到显著阻滞（P＜0.01）。

Male mice were treated with cyclophosphamide (CY) and then serially mated to superovulated female mice over the whole spermatogenic cycle. Chromosome preparations were made from fertilized ova obtained from the mating. No chromosomally abnormal ova were found in mating using untreated animals, but mating involving CY - treated males induced a variety of abnormalities. The most sensitive stage in the spermatogenic cycle was 8 days after treatment， corresponding to the testicular sperm stage of spermatogenesis. The spermatozoa concentration and activity in mice treated with CY at the same stage were not significantly inhibited, but the fertilizing ability of sperm in vitro was decreased, as well as the embryo development was remarkably delayed as compared to those in controls (P<0. 01).