Infertility in men is usually caused by problems that impact either production or transportation of sperm. Through medical testing, the doctor may be able to find the exact reason of the problem.

About 2 of 3 infertile men have a problem with sperm quality. The reasons could either be low numbers of sperm or poor quality of sperm.

Sperm transport issues are found in about 20% of infertile men, including men who in past, have had a vasectomy but now wish to have children. Obstructions in the tubes leading sperm away from the testes can cause a complete absence of sperm in the semen.


Reproduction in females  is controlled by a system that involves the hypothalamus (in brain), pituitary gland, ovaries, and glands  such as the adrenal glands and thyroid gland. Problems with ovulation (release of an egg) result when one part of this system malfunctions. For example,

  • The pituitary gland may produce too little luteinizing hormone or follicle-stimulating hormone.
  • The hypothalamus may not secrete gonadotropin
  • The pituitary gland may produce too much prolactin, a hormone that stimulates milk production.
  • The ovaries may produce too little estrogen.
  • Other glands may malfunction.

Ovulation problems may be caused by  many disorders. One of the most common causes is Polycystic ovary syndrome, which is usually characterized by excess weight and excess production of male hormones.

Other causes of ovulation problems may include the following:

  • Diabetes
  • Obesity
  • Excessive exercise
  • Certain drugs (such as estrogens and progestins and antidepressants)
  • Weight loss
  • Psychologic stress