Remarkable progress has recently been made in embryo transfer technology, resulting in the birth of IVF and nuclear transfer offsprings in swine. However, further progress of the technology to (I) make a safe, effective and economic estrual-cycle synchronization compound, (2) regulate each step of sperm capacitation (3) induce monospermic fertilization, (4) in vitro grow and mature oocytes, (5) fertilize the oocytes efficently, (6) culture the oocytes to the blastocyst stage in defined media, (7) produce multiply copies of embryos with superior genetic merit, (8) preselect the sex of these superior offsprings, and (9) preserve embryos by freezing and storage in liquid nitrogen is required before this promising technology is applied routinely to swine for practical use.

• 박창식(충남대학교 농과대학)