Male infertility refers to the inability of a male to achieve a pregnancy in a fertile female. In humans it accounts for 40-50% of infertility. Male infertility is commonly due to deficiencies in the semen.


Pre-testicular factors refer to conditions that reduce hormonal stimulation of the testes including:
The prostate gland is a small gland that is only found in men. It is located between the penis and bladder and it surrounds the urethra (the tube that carries urine from the bladder to the penis).

The prostate gland helps with the production of semen (the fluid that transports sperm). It produces a thick, white fluid that is liquefied by a special protein called prostate-specific antigen (PSA). The fluid is mixed with sperm, produced by the testicles, to create semen.

There are a number of conditions that can affect the prostate gland including:
  • Low male hormone levels due to various causes such as obesity
  • Drugs and alcohol
  • Strenuous riding, such as bicycle riding and horseback riding
  • Medications, including those that affect spermatogenesis such as chemotherapy, anabolic steroids, cimetidine, spironolactone; those that decrease FSH levels such as phenytoin and those that decrease sperm motility such as sulfasalazine and nitrofurantoin
  • Genetic abnormalities.

Tobacco smoking

Smoking is still controversial in its effect on sperm production.

DNA damage

Inborn faults in the composition of the genetic footprint (DNA) or environmental damage to the DNA molecule might cause sub-fertility.

Testicular factors

Testicular factors refer to conditions where the testes produce semen of low quantity and/or poor quality despite adequate hormonal support and include:
  • Age
  • Genetic defects on the Y chromosome
  • Abnormal set of chromosomes
  • Neoplasm, e.g. seminoma
  • Idiopathic failure
  • Cryptorchidism
  • Varicocele
  • Trauma
  • Hydrocele
  • Mumps
  • Malaria
  • Testicular cancer
  • Acrosomal defects affecting egg penetration
  • Unexplained sperm deficiencies account for 30% of male infertility.
  • Radiation therapy to a testis decreases its function, but infertility can efficiently be avoided by avoiding radiation to both testes.


Post-testicular factors decrease male fertility due to conditions that affect the male genital system after testicular sperm production and include defects of the genital tract as well as problems in ejaculation:
  • Vas deferens obstruction
  • Lack of Vas deferens, often related to a disease (Cystic Fibrosis)
  • Infection, e.g. prostatitis
  • Retrograde ejaculation
  • Ejaculatory duct obstruction
  • Impotence