ICSI is the most successful form of treatment for men who are infertile and is used in nearly half of all IVF treatments (HFEA 2010) .

Intracytoplasmic sperm injection (ICSI treatment) involves injection of single sperm in to an egg in order to cause fertilization. The steps involved are the same as for IVF except that in the laboratory, a single sperm is picked up with a fine needle and injected into the egg.

This is done for all the good quality eggs. ICSI is mainly useful for infertility due to poor quality sperm. In this situation, the couple is unable to have a baby because the sperm cannot enter and fertilise an egg, and ICSI is often the only hope. Pregnancy rates are similar to IVF.