Male infertility is divided into three groups – pretesticular, testicular and post-testicular.

• Pretesticular factors can be both congenital and obtained hypothalamic, pituitary and peripheral organ dysfunction – hypogonadotropic idiopathic hypogonadism, prolactinoma, gonadotrophin synthesis deficiency, or Cushing’s syndrome.
• Testicular factors may be congenital or obtained. Klinefelter syndrome is a genetically inherited male chromosome aberration, which is characterized by additional X chromosome in all cells (47, XXY) or, more rarely, in some of the cells in case of cell mosaicism (mos 47, XXY/ 46, XY), and is characterized by the lack of male hormone production from the testicles. Factors that are not attributable to heredity may be associated with medication use, infections, trauma, and varicocele.
• Post-testicular factors are those related to impaired sperm transport through the tubular system. Post-testicular factors may be congenital or obtained. Congenital bilateral vas deference shortfall may occur in men who suffer from cystic fibrosis. Also, infections, surgery, and trauma can cause tubular closure.