Intracytoplasmic sperm injection (ICSI, is an IVF procedure in which a single sperm is injected directly into an egg. A single sperm is injected into the cytoplasm of a ‘ripe’ egg (oocyte), resulting in fertilization. The treatment has been used for over 10 years with differing degrees of success. This procedure is most commonly used to overcome male infertility problems, although it may also be used where eggs cannot easily be penetrated by sperm, and occasionally as a method of in vitro fertilization, especially that associated with sperm donation. Successful fertilization of eggs is quite high at about 50 to 80 percent, with a lower 30 percent chance of giving birth to a healthy baby.