|
Increased temperature of the testes | Disorders that cause a prolonged fever |
| Hyperprolactinemia (high levels of prolactin, a hormone that stimulates milk production) Hypothalamic disorders (the hypothalamus is the part of the brain that controls the pituitary gland, which controls testosterone production) |
| Other disorders that cause an abnormality in the sex chromosomes |
| Shrinking of the testes (as can occur when excess alcohol is regularly consumed) |
Medications and other substances | Alcohol, when consumed in large amounts Androgens (male hormones such as testosterone) Antiandrogens (medications 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 medication) Cimetidine (used to treat stomach ulcers) Colchicine (used to treat gout) Corticosteroids taken by mouth (such as prednisone) Cotrimoxazole (an antibiotic) Cyclophosphamide (a chemotherapy medication) Medications used to treat malaria Estrogen-like compounds taken to treat prostate cancer Medroxyprogesterone (a synthetic female hormone) Methotrexate (a medication that suppresses the immune system) Monoamine oxidase inhibitors (MAOIs—a type of antidepressant) Nitrofurantoin (an antibiotic) Spironolactone (a diuretic) |
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 |
Disruption of the sperm’s passage out of the body | 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 |
| Nervous system dysfunction Pelvic surgery, such as prostate removal |
|
| Brain and nerve (neurologic) disorders, such as Alzheimer disease Alzheimer Disease Alzheimer disease is a progressive loss of mental function, characterized by degeneration of brain tissue, including loss of nerve cells, the accumulation of an abnormal protein called beta-amyloid... read more , Parkinson disease Parkinson Disease (PD) Parkinson disease is a slowly progressive degenerative disorder of specific areas of the brain. It is characterized by tremor when muscles are at rest (resting tremor), increased muscle tone... read more , multiple sclerosis Multiple Sclerosis (MS) In multiple sclerosis, patches of myelin (the substance that covers most nerve fibers) and underlying nerve fibers in the brain, optic nerves, and spinal cord are damaged or destroyed. The cause... read more , stroke Overview of Stroke A stroke occurs when an artery to the brain becomes blocked or ruptures, resulting in death of an area of brain tissue due to loss of its blood supply (cerebral infarction). Symptoms occur suddenly... read more , and nerve damage due to prostate surgery Psychological problems, such as performance anxiety or depression Certain medications, such as some antidepressants, certain hormonal medications, and medications used to treat high blood pressure (including beta-blockers) Recreational medications (such as cocaine, heroin, and amphetamines) Unknown causes (idiopathic) |