Since the first report of successful spermatogonial transplantation issued by Brinster's laboratory in 1994, some important new findings has been revealed by a series of recently studies relating to spermatogonial transplantation. It has been found that germ cell can be transferred not only from one animal to another, but also from one species to another，which is a big technological breakthrough in the male reproductive researches, especially for the study of Sertoli-germ cell interaction. In essence, Brinster's laboratory has pioneered another transgenic technology that is capable of modifying the entire genome of the animal.