Conventional IVF has been useful for the treatment of some male infertility but success rates drop for those with severe male factor problems. In most cases, the problem is essentially due to the

sperms' inability to penetrate the outer membrane of the egg, and thus resulting in failure of fertilisation. ICSI bypasses this obstacle by injecting a single sperm into an egg.

Since the early nineties, ICSI has been available to couples with Male-Factor infertility. It has allowed many couples to achieve a pregnancy where previous IVF fertilization had been unsuccessful. ICSI fertilization rates are typically between 55-65% of all oocytes injected, and only mature oocytes can be injected.

Generally speaking, if sperm counts are normal, most couples are advised in their treatment care plan to have routine IVF. Sometimes the couple will have borderline sperm samples and in these circumstances they will have some of their eggs inseminated (IVF) and the rest injected (ICSI). However in circumstances where it is clearly evident that there is severe male infertility present, ICSI is the only option.