Published online by Cambridge University Press: 02 December 2021
Since the establishment of in vitro fertilization, it became quickly apparent that approximately half of the couples treated presented with a dysfunctional male gamete. To alleviate this issue, intracytoplasmic sperm injection (ICSI) was introduced to treat men with compromised semen parameters or azoospermia, and more recently high sperm chromatin fragmentation or sperm-linked oocyte activation deficiency. Because of its success, ICSI has been extended for cases with low egg yield, oocyte cryopreservation, and often for preimplantation genetic testing. Due to its versatility and reliability, ICSI has become the most popular ART and will be invaluable for emerging technologies such as in vitro gametogenesis and heritable genome editing. In this chapter, we discuss the development of ICSI, its current applications, and ongoing research that will contribute to the future of reproductive medicine.