Good fertility requires a high sperm count, and good sperm motility of healthy sperm. Low sperm count (Oligospermia), and poor sperm quality (Asthenospermia), are the two main reasons for over 90% of male infertility cases. Abnormal sperm morphology (Teratospermia) caters for the rest of the male infertility cases.
The production of healthy sperm in adequate quantities is important to maintain fertility. A number of factors may affect sperm production; some common factors affecting the quality and quantity of sperm are listed below.
Genetic Problems
The chromosomes may not be coded correctly, causing a problem with the production of sperm. Examples include Klinefelter’s Syndrome and Down’s Syndrome; in the latter, the male is born with one Y and two X chromosomes (rather than one of each), whilst in the latter, the male has an additional full or partial copy of chromosome 21. Another genetic problem is Y chromosome deletion. Any number of genetic problems can cause infertility in males, the majority of which are not easily treated.
Undescended Testes
This is a failure of the testes to descend at birth and it is associated with decreased fertility. Usually a boy’s testes will descend by the time he reaches the age of nine months. One in twenty boys suffer from this condition known medically as Cryptorchidism. It is also related to a higher risk of torsion, hernia, as well as testicular cancer.
Torsion
This is when the testes get twisted inside the scrotum, leading to a problem in sperm production. The twisted blood vessels are unable to feed the testes and considerable swelling is found in the region. If the blocked blood vessels are not treated quickly the condition can lead to permanent infertility. Surgical intervention is required to rectify this problem.
Varicocele
This is when there is enlargement of the veins flowing from the abdomen into the scrotum. The enlargement causes flow of blood from the abdomen into the scrotum, affecting the production and quality of sperm. Alternatively it is called varicose veins of the testes. It is one of the most common causes of male infertility, affecting 40% of males. It is also the most common reversible male infertility problem.
Infections
If a male has suffered from infections such as epididymitis (inflammation of the epididymis), orchitis (inflammation of the testicles), gonorrhoea (bacterial infection), sexually transmitted infections such as HIV (human immunodeficiency virus), it can result in testicular damage. Infections can cause problems in sperm production and quality of that produced.
Hormonal Imbalance
The testicles, the hypothalmus, and the pituitary gland must all secrete testosterone, Antidiuretic Hormone (ADH), Oxytocin (OXT), Follicle Stimulating Hormone (FSH), and Luteinizing Hormone (LH) in proper amounts for the sperm to be produced. Any imbalances from the thyroid or adrenal gland can result in problems for sperm production.
Radiation Damage
Frequent exposure to radiation from X-rays, or even overheating the testicles from using the laptop for long stretches of time can cause problems for sperm production. Issues can also arise from wearing very tight clothes around the scrotum, as well as excessive use of saunas and hot tubs. High temperature of the scrotum sac can reduce the sperm count. Exposure to heavy metals like lead can also cause infertility.
Drugs and Medicines
For males who have been prescribed heavy medication for pre-existing ailments such as mumps, typhoid, tuberculosis, influenza, brucellosis, smallpox and syphilis can also experience problems. The prescribed medication may also affect the rate of sperm production. Those using illicit drugs such as anabolic steroids may have shrunk their testicles, affecting their ability to produce adequate sperm. Use of cocaine, marijuana and the like also affect the sperm produced.
Industrial Chemicals
Those males who are working with hazardous industrial chemicals and have prolonged exposure to benezenes, xylene, toluene, painting material, solvents, herbicides and pesticides, may find sperm production problems affecting them. Such exposure often results in low sperm counts due to the chemical’s effect on the immune system.
Smoking and Drinking
Addictive behaviour of any kind is likely to affect fertility. Smoking tobacco and drinking alcohol in excess with result in reduced sperm counts. Second-hand smoke is just as likely to affect male fertility. The effects are temporary and avoiding the addictions will eventually reverse the infertility caused.
Undefined Causes
While diagnostic tests can figure out the reason for most sperm production problems, there are still a minor percentage of males who suffer from infertility without any known or identifiable reason. The tests may show a low sperm count, or unhealthy sperm being produced but be unable to provide an adequate explanation for why this is happening. Ongoing research is still trying to figure out exactly what goes wrong in such cases to cause male infertility.
References
Further Reading
Understanding the role of genetic variants in male infertility