The development of 2-cell mouse embryos to the blastocyst stage in vitro has been used as a quality control for the media empolyed for human in vitro fertilization. There was a comparison between the quality control data of the culture medium as ascertained by 2-cell mouse embryos development and sperm motility and the data from fertilization and cleavage of human oocytes. However, there was no obvious association between fertilization and cleavage of human oocytes and the quality of the medium ascertained by mouse embryo development and sperm motility.