Persons most commonly affected: Males of fertile age.

Organ or part of body involved: Male reproductive system.

Symptoms and indications: The finding of azoospermia often comes as a surprise since there often are no symptoms (there frequently is an ejaculate and a normal ejaculation process). It is only detectable only by performing a sperm count.

Causes and risk factors: The causes are lack of sperm production due to hormonal problems.