What Causes Infertility in Men?
Cause |
Examples |
Reduced sperm production |
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Increased temperature of the testes |
Excessive heat Disorders that cause a prolonged fever |
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Hormonal disorders |
Adrenal gland disorders (this gland produces testosterone and other hormones) Hyperprolactinemia (high levels of prolactin, a hormone that stimulates milk production) Hypogonadism (low levels of testosterone and/or impaired production of sperm), sometimes related to obesity Hypothalamic disorders (the hypothalamus is the part of the brain that controls the pituitary gland, which controls testosterone production) |
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Genetic disorders |
Other disorders that cause an abnormality in the sex chromosomes |
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Disorders of the testes |
Infections Injury to the testes Mumps that affects the testes (mumps orchitis) Shrinking of the testes (as can occur when excess alcohol is regularly consumed) Tumors in the testes Undescended testes (testes that remain in the abdomen rather than move to the scrotum) Varicose veins in the testes (varicocele) |
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Drugs |
Anabolic steroids Alcohol, when consumed in large amounts Androgens (male hormones such as testosterone) Antiandrogens (drugs that counteract the effects of androgens, such as bicalutamide, cyproterone, and flutamide) Aspirin when taken for a long time Caffeine when consumed in excessive amounts (possibly) Chlorambucil (a chemotherapy drug) Cimetidine (used to treat stomach ulcers) Colchicine (used to treat gout) Corticosteroids taken by mouth (such as prednisone) Cotrimoxazole (an antibiotic) Cyclophosphamide (a chemotherapy drug) Drugs used to treat malaria Estrogens taken to treat prostate cancer Gonadotropin-releasing hormone (GnRH) agonists (hormonal drugs used to treat prostate cancer, fibroids, endometriosis, and other disorders) Ketoconazole Marijuana Medroxyprogesterone (a synthetic female hormone) Methotrexate (a drug that suppresses the immune system) Monoamine oxidase inhibitors (MAOIs—a type of antidepressant) Nitrofurantoin (an antibiotic) Opioids (narcotics) Spironolactone (a diuretic) Sulfasalazine (an antibiotic) |
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Exposure to industrial or environmental toxins |
Heavy metals, such as lead Pesticides (which can have effects similar to those of female hormones or decrease the effects of male hormones) Phthalates (chemicals used to make plastics more flexible) Polychlorinated biphenyl compounds (PCBs) |
Absence of sperm in semen |
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Disruption of the sperm’s passage out of the body |
Missing epididymides (which provide the space and environment for sperm to mature), usually in men with cystic fibrosis Blocked or missing vasa deferentia (tubes from the epididymides to the ejaculatory ducts), usually in men with cystic fibrosis Missing seminal vesicles (which provide nourishment for sperm) Blockage of both ejaculatory ducts |
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Retrograde ejaculation (semen travels back into the bladder rather than out of the penis) |
Diabetes mellitus Nervous system dysfunction Pelvic surgery, such as prostate removal Removal of lymph nodes in the area behind the abdomen (as may be done to treat Hodgkin lymphoma) |
Erectile dysfunction (the inability to attain or maintain an erection sufficient for sexual intercourse) |
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Blood vessel disorders Diabetes mellitus Brain and nerve (neurologic) disorders, such as Alzheimer or Parkinson disease, multiple sclerosis, stroke, and nerve damage due to prostate surgery Psychologic problems, such as performance anxiety or depression Certain drugs, such as some antidepressants, certain hormonal drugs, and drugs used to treat high blood pressure (including beta-blockers) Recreational drugs (such as cocaine, heroin, and amphetamines) Unknown causes (idiopathic) |