from the fertility booklet The A.R.T. of Fertility: A patient guide
by the Fertility & IVF Center of Miami

In some cases of male infertility, the usual mixing of egg and sperm may not result in a fertilized egg. A technique termed ICSI (intracytoplasmic sperm injection) in which a single sperm is injected directly inside the egg with a microscopic needle, may offer a solution to those with severe male infertility. This technique is performed in the laboratory the day of the retrieval using mature eggs.