The main types of IVF are in vitro fertilization-embryo transfer (IVF-ET) and single sperm intracytoplasmic injection. In vitro fertilization-embryo transfer (IVF-ET, also known as the first generation of IVF) is mainly suitable for: 1. tubal infertility; 2. ovulation disorders; 3. endometriosis; 4. male partner with low or weak spermatozoa; 5. unexplained infertility; 6. female immune infertility; 7. multiple failed IUIs. Intracytoplasmic sperm injection (ICSI, also known as second-generation IVF) is an important treatment for male infertility and is suitable for: 1) severe oligospermia, weak spermia, and teratozoospermia; 2) azoospermia or spermatogenic dysfunction confirmed by testicular biopsy or epididymal puncture; 3) male immune infertility; 4) IVF-ET fertilization failure or low fertilization rate.