You might have a problem that keeps your testicles from making sperm or that stops sperm from getting out of your body. There are three main types of azoospermia :

Pretesticular azoospermia : Your testicles are normal, but your body can’t get them to make sperm. It might happen because of low hormone levels or after you’ve had chemotherapy. This type is pretty rare.

Testicular azoospermia : Damage to your testicles keeps them from making sperm normally. It can happen because of :

• An infection in your reproductive tract, such as epididymitis and urethritis
• A childhood illness such as viral orchitis, which causes swelling of one or both testicles
• A groin injury
• Cancer or its treatments, like radiation
• Genetic conditions, such as Klinefelter’s syndrome

Post-testicular azoospermia : Your testicles make normal sperm, but something keeps them from getting out, like :

• A blockage in the tubes that carry sperm from your testicles to your penis. This is called obstructive azoospermia.
• A vasectomy
• Retrograde ejaculation, when semen goes into your bladder instead of out of your penis during an orgasm

About 40% of men with azoospermia have the post-testicular type.