Abstract:Abstract The embryo developmental capacity after in vitro fertilization with the X-sorted frozen and unsorted frozen sperm were studied. The cleavage and blastocyst rate of embryos fertilized with X-sorted frozen sperm, were significantly lower than that of control group fertilized with unsorted frozen sperm (51.4% vs. 67.9%, P< 0.05; 19.7% vs 29.9 %, P<0.05 ). After the two kinds of frozen sperm were treated with the micro epi-floating non centrifugation and the epi-floating , the cleavage rate of the former was better than that of the latter, but there were not statistically significant difference (50.7% and 65.5% vs. 48.3% and 63.8%, P>0.05). Additionally, no statistical differences were observed in morula rate and blastocyst rate of the cleavaged zygotes fertilized with the X-sorted frozen sperm and unsorted frozen sperm. After co-culturing with sertoli cells and granular cells respectively, the cleavage rate (50.0% and 51.4%) of sexed zygotes co-cultured with feeder cells were not statistically significant difference with that of control group (50.3%, P>0.05). And the morular rate(53.3% and 54.6%) and blastular rate (21.1% and 21.5%) of sexed embryo co-cultured with feeder cells were higher than that of control group (52.2% and 20.4%), but there were no statistically difference (P>0.05).