Causes of male infertility

This section covers some of the main causes of infertility in men.

Blockage of the sperm tube

Many diseases can cause inflammation of the vas deferens, or sperm tube, and result in scarring which can block the tube passing sperm from the testicles or testes. Infections from untreated sexually transmitted infections, such as gonorrhea and chlamydia, can also ascend via the urethra. Other conditions which can cause inflammation of the epididymis in the testes and disrupt the production of sperm are tuberculosis, schistosomiasis, and the abnormal growth of tumours in the testicles.

Problems of sperm production and quality

Many disorders lead to abnormal or reduced sperm production, and can result in it stopping altogether. For example, mumps contracted in childhood can lead to inflammation and/or shrinking of the testes, thereby stopping sperm production in adulthood. Drinking large amounts of alcohol can also reduce production of testosterone (the male hormone) and cause shrinking and/or weakness of the testes. Other factors such as the testes failing to descend from the abdomen, excessive smoking and drug abuse, excessive heat due to wearing tight underwear, or working for long periods near a heat source, can reduce the production and motility of sperm.

Sexual problems

Certain psychological conditions, like emotional, psychological or physical stress, can result in the inability to maintain an erection, and the inability to ejaculate normally inside the vagina. Impotence and premature ejaculation, where the man ejaculates before the penis is inside the woman's vagina, are another common cause. Other factors which contribute to a man not achieving normal sexual intercourse include neurological damage due to leprosy, taking medications such as methyldopa (an anti-hypertensive drug), surgery involving the penis, scrotum, prostate or pelvis, that can cause nerve damage, and alcohol consumption. In addition, certain chronic diseases like diabetes can reduce the ability to have, and maintain, an erection due to vascular changes.