Abstract
In vitro fertilization and embryo transfer (IVF-ET) has been applied to human fertility treatments for 30 years and its clinical usefulness has been established, its safety and availability have improved and steady success rates have been achieved.
However, the pregnancy rate per cycle has not changed over the years and remains not more than 30%.
In order to improve the success rate, certain problems must be addressed and resolved. These problems are (1) primary azoospermia, (2) aging oocytes, (3) habitual miscarriage and (4) X linked recessive inheritance.
We have tried new approaches to resolve these problems through microfertilization using spermatids, in vitro culture of immature spermatogenic cells, oocyte donation, nuclear transfer, pre-implantation genetics diagnosis and X or Y sperm separation using infrared spectroscopy.
