Causes of Male Sterility

Testicular Function Impairment

Reduced sperm quality can affect all three main factors (sperm count, mobility, and percentage of sperm with normal morphology). This has also been linked to infection-induced testicular damage (mumps), testicular varicose veins (varicocele), or occupation-related pressure or temperature influences and also radiation exposure. Undescended testicles that were not treated early enough in childhood also often lead to a reduction in sperm quality.

Malformation or Occlusion of the Spermatic Duct

Certain types of genetic disorders or inflammation can lead to incorrect development or adhesions of the ejaculatory spermatic ducts. Here, highly febrile mumps can play an important role. In this case, no sperm are found in the ejaculate; however, a testicular biopsy can be used to collect germ cells and then used in fertility treatment.

Hormonal Disorders

In rare cases, hormonal disorders can be the cause of impaired sperm production. A not uncommon example of a self-inflicted hormonal imbalance is the use of anabolic steroids.

Immunological factors

For example, with a long-term accumulation of sperm, either as a result of infection or vasectomy, it is suspected that the body creates antibodies to combat its own sperm, and this reduces their ability to fertilise the egg cell.

After Vasectomy

A vasectomy is a method of male contraception causing there to be no sperm found in the produced ejaculate.

Neurological and Psychological Factors

Erectile or ejaculation-related disorders can result from paraplegia or the removal of tumours from the genital area. In the case of retrograde ejaculation, the ejaculation takes place but in the wrong direction, i.e. into the bladder.
Psychological disorders can reduce sex drive and lead to erectile dysfunction or ejaculatory disorders which can prevent pregnancy.

Chromosomal Disorders

Certain types of chromosomal disorders affect the maturation of the sperm in the testicles. In this case,  even in  a testicular biopsy (testicular tissue sample collection) there are no  mature sperm found that would able to fertilise an egg cell.

Malformation

There are penile developmental disorders where the urinary tract does not end in the glans but rather in the penile shaft. Consequently, during ejaculation, the sperm cells are unable to reach the cervix.