Sperm-mediated gene transfer(SMGT)appears to be a simple,efficient,and inexpensive method for genome modification of animals.DNA uptake by the mammalian spermatozoa is a very specific and highly regulated phenomenon.The sperm parameters,such as sperm donor,plasma membrane,sperm quality,and the treatment methods affect not only the ability and efficiency of sperm to pick up exogenous DNA and to internalize the DNA into sperm nuclei,but also the vector type and transfection method used.The efficiency of picking up exogenous DNA by goat spermatozoa decreases with age.Different goat breeds exhibit different abilities in binding foreign genes.Selection of sperm donors and optimization of DNA uptake are the key steps for the successful outcome of SMGT.The use of frozen-thawed spermatozoa is an efficient method for production of transgenic offspring.