Causes of Male infertility

Male infertility is mostly due to low sperm concentration in semen ( oligozoopsermia ), absent sperm in semen ( azoopsermia ), weak sperm motility ( asthenozoopsermia ), increase in sperm abnormal forms ( teratozoopsermia ) or due to low capability of fertilizing the ovum despite normal concentration, motility and shape.

Less commonly, the causes of male infertility are due to  failure to deposit semen in the right part of the vagina such as the case with impotence, curvature of the penis, hypospadias (abnormal position of the urine outlet) or severe premature ejaculation.

Low sperm concentration (oligozoospermia) or total absence of sperm (azoospermia) are due to either low activity of the testis (functional) or due to occlusion of the sperm outlet (Vas deferens) in which case infertility is termed (obstructive).


Obstructive Infertility ( obstructive azoospermia or oligozoospermia )

Occlusion of the vas deferens leads to infertility, since it is the tube that conveys sperm to the urethra in the penis.

In such cases, semen may still be ejaculated despite sperm being absent, since the seminal fluid is not produced in  the testis, but rather in the seminal vesicles and prostate.. Obstruction just beyond the testis may still allow seminal fluid to be ejaculated.

Obstruction may be on one side or both sides. It may be partial or complete.

Obstruction occurs due to repeated infections, mistakes at surgical procedures, or inborn congenital abnormalities.

Infections that reach the genital system may be due to sexually transmitted ddiseases such as gonorrhoea and chlamydia, due to infection of urine commonly caused by stones, where the infected urine forces itself down the vas deferens upon straining. It can also spread from distant infections in the body such as from the rectum.

Infection results in the formation of pus, inflammation and fibrosis (solid tissues that are formed to repair wounds and dead tissue). The accumulation of those results in obstruction of the vas.

Obstruction may result from mistakes during surgery especially surgery that is performed along the course of the vas deferens such as hernia repair, varicocelectomy and testicular biopsy.

Dr.Shaeer, the author of this site has invented a surgical technique for treating such cases. This technique is published and applied world-wide.

Inborn congenital abnormalities include total absence of the vas deferens, whether on one or both sides, or presence of a spherical mass (cyst) at the point of union of both vasa deferentia (the ejaculatory ducts). Absence of he vas deferens may be associated with abnormalities in the kidney and ureter, which is why imaging is necessary to confirm their status.

Infertility due to Decreased Activity of the Testis (Functional azoospermia or oligozoospermia / Non-obstructive azoospermia or oligozoospermia)

This is when the decrease in or absence of sperm is due to weak spermatogenesis (sperm production). This may be caused by any of the following:

Varicocele and infertility:

This is a disease that affects veins of the testis. A vein is the blood vessel that carries blood out of the testis, contrary to arteries, which are the blood vessels that carry blood into the testis. The blood flows out of the testis in the veins carrying waste products away, waste products such as carbon dioxide, heat..etc.

In case of varicocele, the veins become dilated and tortuous more than they should be. This leads to stagnation (accumulation) of blood in the veins, and  cconsequently, accumulation of the aforementioned waste products around the testis. The accumulation of those waste products leads to damage of the testis and infertility. However, they have no effect on sexual performance since they affect the sensitive sperm-producing cells, and not the sturdy hormone-producing cells that produce testosterone.

varicocele is when the testicular veins become dilated and tortuous more than they should be. This leads to stagnation (accumulation) of blood in the veins, and  cconsequently, accumulation of the aforementioned waste products around the testis.
Normal spermatic cord versus varicocele

In the presence of a varicocele on one side, the other side is affected as well due to the communication between both testes. Most commonly, varicocele occurs either on both sides or on the left side. It rarely occurs on the right side solely.

At the very beginning, the testis produces sperm in a concentration higher than normal and motility / morphology are normal. Gradually, sperm production decreases both in quality and quantity, leading to decrease in sperm concentration, motility, normal forms, and above all, a decrease in fast forward motility and in the capability of fertilizing the ovum. The latter does not show in a normal semen analysis. Therefore, a normal semen in the presence of infertility and a varicocele may mean that sperm fertilization capacity is abnormal. Eventually, in long standing larger grades of varicocele, the testis becomes small and soft (atrophy), with no sperm production. Varicocele may cause infertility regardless its grade, whether small or large. Naturally, the larger the varicocele, the faster the deterioration is.

What causes varicocele? This is usually a family predisposition where there is weakness of the body walls (congenital weakness of the mesenchyme) affecting blood vessels (varicocele and leg varices) or abdominal wall (hernia). In many cases, the cause is unknown, but the onset of varicocele is aided by habitual straining such as in cases of long standing constipation, long standing cough (smokers), weight lifting and prolonged standing. Rarely, varicocele is caused by an abdominal mass. This is suspected if varicocele occurs only on the right side.

What are the symptoms of varicocele? Usually there are no symptoms and varicocele is discovered when infertility occurs. Sometimes, in large grades of varicocele, there may be pain or heaviness, or there may be a whitish drop that comes out of the penis following urination or defecation. 

Undescended Testis and and infertility:

The testes develop inside the abdomen (upper back) while a fetus is still in the uterus. It starts making its way down to its normal position in the scrotum starting the 4th month of pregnancy, and reaches it destination on the 8th month.

Sometimes, this descent fails and the testis is trapped at any point along the course of its descent: Undescended testes. The testis may become trapped inside the abdomen, within the layers of the anterior wall of the abdomen (inguinal canal), or at the neck of the scrotum.

The reason for failed descent may be genetic (abnormality of the chromosomes) or mechanical (presence of a hernia that traps the testis).

Eentrapment inside the abdomen leads to ooverheating of the testis, resulting in infertility and possibly tumor formation. It is therefore that the testis MUST be taken out of the abdomen whether by bringing it down to its normal place if possible (orchiopexy) or by total removal of the testis (orchiectomy) to avoid the formation of tumors (if descent is not possible). Heat affects the sensitive sperm-producing cells and not the sturdy hormone-producing cells. Therefore infertility occurs but impotence and low verility do not occur. Even if both testes have to be removes, impotence and decreased masculinity will not occur (provided testosterone injections are used every 4 months)

Usually the undescended testis produces absolutely no sperm. Bringing down the testis to its normal place (orchiopexy) in early childhood may help resuming sperm production. Orchiopexy at adulthood is absolutely necessary for avoiding tumors, and may rarely help with sperm production.

Diagnosis: the position of the testis can sometimes be determined  by ultrasonography, CT or MRI. If they fail to demonstrate the testis, laparoscopy is necessary to confirm its presence or absence. Laparoscopy is also the way by which the testis is brought down or removed.

Retractile Testis:

Is a condition where the testis is trapped in a position higher than normal, but can occasionally settle down to its normal position. That is, it moves up and down. This condition does not affect fertility unless the testis is pressed or hit at its higher position. Surgical correction may be indicated for cosmetic reasons. Hormonal treatment for this condition is controversial. Hormonal treatment is based on the assumption that the hormones will increase the size and weight of the testis, and thus being heavy it will not go up. This is possible only in childhood, but has the disadvantages of possible mild masculinization and shorter height of the child. Moreover, some adults have a large and heavy testis that still goes up and down (retractile) despite its weight.

Congenital Abnormalities

These are inborn abnormalities due to defects in genes and or chromosomes.

Examples are:

Klinefilter (KF) Syndrome

Klinefilter (KF) Syndrome is when there is an extra “X” chromosome in a male, leading to a total number of47 chromosomes instead of 46, and infertility. The testis stops producing sperm and is small and form. The mixed form of this condition (Mosaic form) may carry the possibility of sperm production to a little extent, contrary to the absolute form.

Kallmann’s Syndrome

Kallmann’s Syndrome is where the hypothalamus (part of the brain) does not produce the stimulating hormone (GnRH) necessary for the activity of the pituitary gland, that in turn stops producing the hormones  (FSH and LH) necessary for stimulating the testis. Therefore the testis stops producing sperm and testosterone, leading to infertility, impotence ad hypogonadism.

 Some congenital abnormalities affect the sperm itself rather than affecting the testis and affecting sperm production. Examples include absence of some of the internal elements of the sperm tail and absence or disturbance of the acrosomal cap necessary for fertilization.

Hormonal Abnormalities and infertility:

A rise in prolactin or estrogen levels results in infertility and impotence. Rise in prolactin level may sometimes be due to a brain tumor. Rise in estrogen levels may be due to a tumor of the testis. It is therefore nnecessary to perform imaging investigations to check both.

A drop in testosterone level or FSH level may produce infertility. This may be due to an abnormality of the hypothalamus or pituitary, present in the brain, both of which produce hormones that work together to activate the testis.

Infections and infertility

Some infections may damage the testis partially or totally. The most famous is “Mumps”, which is a virus that affects the parotid gland and the testis at childhood. Other infections include gonorrhoea and leprosy.

Radiation and infertility

Accidental or habitual exposure to irradiation damages the testis unless adequate safety measures are taken. Radiation include Xray, CT, MRI, atomic and nuclear irradiation. Damage depends on the dose received and on the duration. If the dose is not too high, the testis may return to normal activity after a number of years depending on the dose.

It is therefore necessary to follow up semen analysis as long as exposure is ongoing and to preserve sperm by cryopreservation before exposure to irradiation such as in tumor patients intending radiotherapy.


Some chemicals decrease testicular activity down to complete arrest of sperm production, Those include chemotherapy for tumors, Petroleum derivatives, Lead, insecticides, estrogenic chemicals..etc

It is therefore necessary to decrease exposure as much as possible, to followup semen analysis as long as exposure is ongoing, and to preserve sperm by cryopreservation before exposure.


Excessive heat exposure over long periods leads to infertility. This is possible in individuals working in the iron industry, next to ovens and those driving heavy machinery emitting heat. It is again necessary to followup semen analysis as long as exposure is ongoing

Accidents / Trauma

Trauma and accidents affecting the testis may lead to infertility. Examples are direct kicks, blows, and falling astride an object. Trauma may lead to perforation / rupture of the external wall of the testis (tunica albuginea), with expulsion of the sperm producing tissue to the outside and massive bleeding. It is necessary to consult a specialist as urgently, especially if a swelling occurs, to determine the need for surgical repair. The decision is made by ultrasonography.

Testicular Torsion

Torsion of the testis is a condition when the testis rotates around its vertical axis, with subsequent rotation and occlusion of the blood vessels, leading to death of the testis within six hours
Testicular Torsion

The testis receives blood vessels from the body, some of which are feeding vessels pouring blood into the testis (arteries), and others are draining vessels carrying blood and waste products away from the testis (veins).

Torsion o the testis / Testicular Torsion is a condition when the testis rotates around its vertical axis, with subsequent rotation and occlusion of the blood vessels, leading to death of the testis within six hours.

Torsion leads to severe sudden pain. It requires immediate consultation of a specialist to determine the necessity of immediate surgical correction. Diagnosis is established by ultrasonography. The latter measures the blood flow in the painful testis in comparison to the normal one. If blood flow is less in the painful one, the condition is diagnosed as torsion. If the flow is higher, then it is a case of inflammation of the testis (epididymo-orchitis). Epididymo-orchitis requires medical treatment, while torsion requires surgical treatment.


Some tumors affect the testis. Whether benign or malignant, they lead to erosion and death of the sperm producing tissues. Some tumors secrete feminine hormones such as estrogen.

Diagnosis of testicular tumors is by ultrasonography and blood analysis. Blood analysis include hormones (that may increase in some cases) and tumor markers (chemicals that increase in case of tumor formation, including beta hCG and alkaline phosphatase)

Before treatment, it is necessary to store sperm by cryopreservation since some treatment modalities impair fertility (surgical excision, chemotherapy or radiotherapy)

Abnormal Sperm Functions

Some diseases impair the capability of sperm to fertilize the ovum such as by decreasing the dissolving enzymes in the acrosome. Such conditions include varicocele and infections. So despite the normal semen concentration, motility and normal forms, the sperm still cannot fertilize the ovum. Some specific tests are capable of diagnosing these conditions such as the “acrosin” test.

Antisperm Antibodies and infertility

Antibodies are molecules produced by the immune system to attack strangers such as microbes. Antibodies should not be produced against one’s own tissues. Unfortunately, this may occur in some diseases called “autoimmune diseases”.

Antisperm antibodies  are antibodies against the sperm They may be produced in the male or in the female’s cervical secretions to attack sperm. This happens whenever sperm leaves the testis and is recognized in the blood by the immune system and is therefore targeted. Sperms enter the blood in case of long standing obstruction (accumulation and high pressure lead to microscopic ruptures and escape of sperm) and in accidents with overt rupture of the testis. Antisperm antibodies stop the sperm from moving and lead to agglutination (entangling of sperm tails)

Antisperm antibodies can be examined in semen, cervical mucous of the female and in blood samples in both partners. The latter is of no clinical significance. Examination is preferably by the indirect MAR test.


Microbes can decrease testicular activity down to total damage of the testis if inflammation of the testis (epididymo-orchitis) occurs, ending in atrophy (decrease in size and loss of function). This  is common with Mumps (air borne virus) gonorrhea (sexually transmitted bacteria) and Ecoli (urinary bacteria).

On the other hand, mild infection can cause infertility by occlusion (obstruction) of the vas deferens, or by decreasing sperm motility and capacity of fertilization.

Infection may spread to the testis from urine, blood, from having sex with a lady who has infections, from toilet seats..etc.

Infection may or may not cause symptoms. It may pass unnoticed but produce infertility.

In case there is pain in the testis, it has to be differentiated from torsion of the testis.

Disorders of Deposition

Semen must be ejaculated at the deepest point of the vagina. If this fails then there is a deposition disorder. Examples are impotence, short or curved penis, extreme premature (rapid) ejaculation where semen is ejaculated before the penis is inserted in the vagina.