In Vitro Fertilization (IVF): The so-called “first generation” of IVF in China refers to the in vitro fertilization-embryo transfer (IVF-ET) technique, which is indicated for infertility caused by female tubal obstruction, endocrine disorders and other reasons. The so-called “second-generation” IVF is the intracytoplasmic monosperm injection (ICSI) technique, which is indicated for infertility caused by low sperm quality of the male partner. The main difference between the “second generation” and the “first generation” is that in the former, a single sperm is injected into the egg cell with the help of microscopic techniques to fertilize the egg, while in the latter, the sperm and egg are combined naturally under laboratory conditions. It follows that when the sperm is of good quality, only the in vitro fertilization-embryo transfer technique needs to be applied. It is only when the sperm quality is low that the intracytoplasmic monosperm injection (ICSI) technique is required. The so-called “third-generation” IVF is a genetic examination of the embryos before they are transferred to the uterus, and then normal embryos are implanted into the uterus, with the aim of eugenic fertilization. The main indications are couples carrying a gene for a pathology, or families with a history of genetic disorders. The embryos used for the test can come from in vitro fertilization-embryo transfer techniques or from intracytoplasmic monosperm injection techniques. More recently, cytoplasmic replacement, a treatment for women with low egg quality, has been referred to as the “fourth generation” of IVF. From the above, it can be seen that in vitro fertilization-embryo transfer (the so-called “first-generation” IVF) mainly solves the problem of infertility caused by females; intracytoplasmic monosperm injection (the so-called “second-generation” IVF) mainly solves the problem of infertility caused by males; and genetic diagnosis before embryo transfer (the so-called “fourth-generation” IVF). Genetic diagnosis before embryo transfer (the so-called “third-generation” IVF) mainly solves the problem of eugenics. 1.In vitro fertilization-embryo transfer (IVF-ET IVF) In 1978, the world’s first in vitro fertilization-embryo transfer (IVF-ET) baby, Louise Brown, was born in the U.K. This new technique of assisted conception has already helped tens of thousands of infertile couples to give birth to healthy children. In vitro fertilization – embryo transfer (IVF-ET) is the application of drugs to induce multiple follicles to mature, when the follicles are mature, the eggs are retrieved under the guidance of vaginal ultrasound, the eggs are removed, the husband retrieves the sperm, and in vitro fertilization is carried out in the laboratory. Matured eggs and sperms are fertilized outside the body to form a fertilized egg, which continues to develop into an embryo, and the best embryos are selected in 2-3 pieces, and are transferred to the uterus to develop into a fetus. The embryos are cultured in vitro for only a few days. The most important purpose is to make sure that the sperm-egg union is successful and that there are remaining good embryos that can be frozen and preserved. In vitro fertilization-embryo transfer is mainly indicated for patients with tubal obstruction, polycystic ovaries with multiple ovulation and intrauterine insemination failures, endometriosis, years of immune infertility, and unexplained infertility. Endometriosis chocolate cysts after first puncture, then in vitro fertilization-embryo transfer, has been successful. 2, Intracytoplasmic Single Sperm Injection (ICSI Second Generation IVF) Intracytoplasmic Single Sperm Injection (ICSI) is mainly applied to male infertility, vas deferens obstruction, congenital testicular dysplasia, oligozoospermia, weak spermatozoa, repeated failure of in vitro fertilization-embryo transplantation, elderly infertile couples, and patients with years of immune infertility. Patients apply super ovulation drugs to promote follicular development, when the follicles are mature, the eggs are retrieved under the guidance of vaginal ultrasound. Some azoospermia patients can apply microsurgical aspiration of epididymal sperm or testicular biopsy to obtain sperm in the laboratory, and fertilize with intracytoplasmic monosperm injection of oocytes under the laboratory microscope to cultivate the embryos, and select the excellent embryos, 2-3, and then carry out the embryo transfer. 3.Pre-implantation Genetic Diagnosis (PGD 3rd generation IVF) It refers to genetic examination of embryos before embryo transfer to the uterus, and then implanting normal embryos into the uterus, the significance of which lies in eugenics. The main indications are couples who carry a gene for a disease, or families with a history of genetic disorders. The embryos used for the test can come from either the in vitro fertilization-embryo transfer technique or from the intracytoplasmic monosperm injection technique.