Infertility In Males
Infertility (in-fer-til′i-t̄e) is reduced or diminished fertility. Themost common cause of infertility in males is a low sperm cell count. If the sperm cell count drops to below 20 million sperm cells per milliliter, the male is usually sterile.
The sperm cell count can decrease because of damage to the testes as a result of trauma, radiation, cryptorchidism (See Clinical Impact “Descent of the Testes”), or infections, such as mumps, which block the ducts in the epididymis. Reduced sperm cell counts can also result from inadequate secretion of luteinizing hormone and follicle-stimulating hormone, which can be caused by hypothyroidism, trauma to the hypothalamus, infarctions of the hypothalamus or anterior pituitary gland, or tumors. Decreased testosterone secretion reduces the sperm cell count as well.
Even when the sperm cell count is normal, fertility can be reduced if sperm cell structure is abnormal, as occurs due to chromo-somal abnormalities caused by genetic factors. Reduced sperm cellmotility also results in infertility. A major cause of reduced sperm cell motility is the presence of antisperm antibodies, which are produced by the immune system and bind to sperm cells.
In cases of infertility due to low sperm cell count or reduced motility, fertility can sometimes be achieved by collecting several ejaculations, concentrating the sperm cells, and inserting them into the female’s reproductive tract, a process called artificialinsemination (in-sem-i-nā′sh̆un).