With the development of in vitro fertilization and assisted reproductive techniques, it has become possible to genetically analyze embryos created by these methods before pregnancy is achieved.
The process of transferring healthy embryos by testing the gene or chromosomal disorder that causes the disease before pregnancy occurs is called "preimplantation genetic diagnosis" or "preimplantation genetic diagnosis (PGD)".
PGTi can be examined under three headings in general.