Conventional fertilization, also known as “one generation IVF”, involves natural conception in which the sperm and oocyte meet in the fallopian tube and unite to form a fertilized egg. The conventional fertilization method of IVF simulates the natural human conception process by mixing the removed oocytes with the treated semen in a certain ratio and placing them in a Petri dish where the sperm overcome various obstacles to enter the oocyte and fuse with the oocyte to complete the fertilization process. First generation IVF requires that the male partner’s semen must not be too poor and the treated sperm must reach a certain number! Microinjection of single sperm (ICSI), also known as “second-generation IVF”, artificially selects a single sperm with good vitality and normal morphology and injects it directly into the oocyte through microscopic manipulation techniques to help complete the fertilization process. This technique mainly addresses the problem of severe oligospermia, weak sperm and malformed sperm in men. Second generation IVF is mainly for male patients with poor sperm count, quality and also some patients who have failed in conventional fertilization. Pre-implantation genetic diagnosis (PGD), also known as “third generation IVF”, refers to the analysis of the genetic material of the embryos before transfer to diagnose any abnormalities and to select healthy embryos for transfer so as to prevent the transmission of genetic diseases to the offspring. IVF III places emphasis on eugenics and is suitable for recurrent miscarriages and monogenic diseases.