Azoospermia

The absence of sperm from semen, causing infertility in males. Azoospermia may be caused by a disorder present at birth or that develops later in life or after vasectomy. Congenital azoospermia may be due to a chromosomal abnormality such as Klinefelter’s syndrome; failure of the testes to descend into the scrotum; absence of the vasa deferentia (ducts that carry sperm from the testes to the seminal vesicles); or cystic fibrosis. In some males, azoospermia may be the result of hormonal disorders affecting the onset of puberty. Another cause is blockage of the vasa deferentia, which may follow a sexually transmitted infection, tuberculosis, or surgery on the groin. Azoospermia can also be the result of damage to the testes. This can follow radiotherapy, treatment with certain drugs, and prolonged exposure to heat, or the effects of occupational exposure to toxic chemicals. If the cause is treatable, sperm production may restart. However, in some cases, the testes will have been permanently damaged.