Most common causes of infertility in men are explained in this article. An exact cause is not known in some cases (known as unexplained infertility).
Sperm Disorders
There are four types of sperm disorders: low sperm count known as Oligospermia, complete absence of sperm cells referred to as Azoospermia, poor sperm motility known as Asthenospermia (inability of the sperm to move fast enough or to move in a straight line) and abnormal sperm morphology referred to as Teratospermia (abnormally shaped sperm). All these conditions interfere with a sperm’s ability to reach and fertilize an egg and are regarded as major causes of infertility in men.
Sperm disorders are results of: birth defects, hormone deficiency in the pituitary gland or hypothalamus, aging, exposure to harmful substances, radiations or high temperature, chemotherapy, sexually transmitted diseases and other lifestyle factors such as smoking, alcohol abuse, use of marijuana or cocaine, excessive exercise, bike riding, stress etc.
Structural Disorders
Most common structural disorders that can cause infertility in men are:
Blocks in Vas Deferens or Ejaculatory Duct: Sperm are transported from testes to penis through vas deferens (a pair of tubes, one from each testicle) and ejaculatory duct. A genetic defect such as cystic fibrosis (click for more information), scarring from tuberculosis or sexually transmitted diseases can cause blockages in vas deferens or ejaculatory duct. This can result in low sperm count or complete absence of sperm cells is semen.
Varicocele: is enlargement of varicose veins around testes. This raises temperature in testes, thereby causing reduced sperm count and abnormal sperm morphology.
Torsion: is characterized by a tissue abnormality which allows testes to twist inside the scrotum, damaging blood vessels and causing swelling. This can lead to sperm disorders.
Cryptorchidism: refers to a condition usually seen in new born babies when one or both testicles fail to descend from abdomen into the scrotum. Cryptorchidism can cause low sperm count and/or poor sperm quality. There are medical treatments available for cryptorchidism.
Hypospadias: is a birth defect in which the urethral opening is not at the tip of the penis. This condition can interfere with transportation of sperm from testes to penis. Hypospadias can be surgically corrected.
Genetic Disorders
Genetic disorders such as the ones listed below can lead to infertility:
Klinefelter Syndrome: Men with Klinefelter Syndrome have two X chromosomes and one Y chromosome (instead of one X and one Y). This can lead to destruction of testicular structures, causing infertility. Klinefelter syndrome can be diagnosed by chromosome analysis and treatments are available if detected in early stages. Click symptoms of Klinefelter syndrome for more information.
Polycystic Kidney Disease: is characterized by growth of cysts in kidneys and other organs. If these cysts start to develop in the reproductive tract, it can lead to infertility.
Kartagener Syndrome: is a rare disorder that can harmfully affect sperm motility (ability of the sperm to move fast enough or to move in a straight line).
Erectile Dysfunction
Erectile dysfunction, also known as impotence is the inability to develop or maintain an erection of the penis. This condition prevents successful ejaculation in men, leading to infertility. Causes of erectile dysfunction include: anxiety, stress, guilt, diabetes, alcohol abuse, obesity, high blood pressure, heart and vascular disease, hormonal problems, injuries to pelvic area or spinal cord and some prescription drugs such as diuretics, antihypertensives, antipsychotics, antidepressants etc.
Premature Ejaculation
A condition in which ejaculation happens before a man fully inserts his penis to partner’s vagina. This can cause infertility, since sperm are not able to move through vagina towards fallopian tube to reach the egg and fertilize it.
Retrograde Ejaculation
In this condition, muscles of the bladder dysfunction and sperm are forced to flow backward into the urinary bladder instead of moving forward to the penis. This could result in low ejaculate volume, low sperm count, low sperm quality and cloudy urine after ejaculation. Retrograde ejaculation can be caused by surgeries to bladder, prostate, urethra or spinal cord, diabetes, aging, use of blood pressure medications, tranquilizers and certain antipsychotic drugs.
Autoimmune Problems
Human body may develop antibodies that mistakenly target and fight sperm cells treating them as foreign bodies. This happens most commonly after a vasectomy (click for more information), injury to testes or infection.
Other causes of infertility in men
Other causes include: tight underwear, malnutrition and anaemia, obesity, injuries to testes, anabolic steroid use, hot baths, imbalances in hormones produced by the pituitary gland or thyroid gland, infections in the reproductive tract, aging, exposure to harmful substances, exposure to radiations or high temperature, chemotherapy, sexually transmitted diseases, lifestyle factors such as smoking, alcohol abuse, use of marijuana or cocaine, excessive exercise, bike riding, stress and diseases such as mumps, tuberculosis, gonorrhea etc.