One-third of infertility cases are attributed to the male, one-third to the female, and the remaining third to both male and female factors. Therefore, male factors play a role in nearly 50-60% of cases.

The male reproductive system essentially begins in the hypothalamus, a region located in the lower part of the brain; it continues with the pituitary gland, also located in the lower part of the brain, and ends in the testes. Infertility causes are evaluated by dividing them according to the anatomical location of these regions, i.e., the reproductive system:

Anatomically pre-testicular causes generally affect the hypothalamus and pituitary gland and usually develop due to endocrine/hormonal disorders. In addition, pre-testicular causes can arise from infiltrative diseases of the pituitary gland, tumors, circulatory disorders, pituitary dysfunction after radiotherapy/surgery, surgical interventions, and certain genetic diseases. These conditions are almost always manifested as hormonal disorders.

Any condition affecting testicular function and impairing sperm production is a cause of infertility: testicular infections, testicular trauma, testicular surgery, undescended testes, exposure to toxic substances affecting the testes (radiotherapy/chemotherapy/workers in lead-battery-mercury industries, etc.), high temperature, pesticides, chemicals; genetic disorders, insufficient testosterone secretion.

Any condition preventing the expulsion of sperm produced in the testes from the male genital system is considered a post-testicular cause of infertility: sperm motility disorders; absence of sperm ducts; disruption of the integrity of sperm ducts due to surgery or sexually transmitted infections resulting in blockage/damage; inability to have intercourse due to sexual dysfunction and penile deformities; absence of semen due to prostate surgery and/or medication use or other causes.