Male infertility has many causes and accounts for more than half of infertility cases.

A man that has no sperm in his semen is said to have azoospermia. This may be because of a blockage in one of the tubes that transfers sperm from the testes, where they were produced, out of the penis during ejaculation.

There are several techniques that can be used to retrieve a large number of sperm that remain inside these tubes:

• Percutaneous Epididymal sperm aspiration (PESA): when the release of sperm is prevented by blockage in the epididiymis, the urologist aspirates this sperm using a needle and syringe technique.
• Testicular sperm extraction (TESE) and testicular aspiration (TESA): the sperm is taken from the testicle itself rather than the epididymis. This is essential when the sperm never reaches the epididymis. This situation is true in most cases of non-obstructive azoospermia.