Current technical projects : Artificial insemination with husband sperm, the first generation of IVF (conventional in vitro fertilization) and the second generation of IVF (intracytoplasmic sperm injection) technology.Technologies that have not yet been developed: the third generation of IVF technology (Preimplantation genetic diagnosis and screening) and mitochondrial replacement technology. Each generation has no grade difference, but it is suitable for different groups of people. The first generation is suitable for husband whose semen is almost normal or slightly abnormal; the second generation is suitable for husband with moderate or severe abnormal semen and conventional IVF failure; the third generation is suitable for couples with genetic diseases who need to do PGD/PGS..