By Zaira Salvador BSc, MSc (embryologist) and Emilio Gómez Sánchez BSc, PhD (senior embryologist).
Last Update: 10/08/2018

Male infertility or sterility is defined as a man’s inability to cause pregnancy in a fertile woman. The set of factors affecting a man’s fertility include pre-testicular, testicular, and post-testicular problems, as well as sperm abnormalities. About 7% of all men have infertility issues, and it accounts for 40-50% of infertility cases in humans. Nowadays, male fertility issues can be treated by means of assisted reproductive technologies (ARTs), such as IUI, IVF or IVF/ICSI.

It is important to understand that, even though the terms infertility and sterility are commonly used interchangeably, they are not synonyms. Each term is defined as follows:

inability to conceive a child.
reduced or lack of ability to conceive a child and carry a pregnancy to term.

The different sections of this article have been assembled into the following table of contents.

Male infertility testing

To determine what could be the cause behind male infertility, a fertility check-up should be carried out. The basic tests to check the fertility of a man include:

  • A physical examination, to evaluate the patient’s overall state of health, as well as his reproductive organs.
  • A semen analysis (SA) to check the quality of the sperm he produces in terms of motility, count, morphology, and vitality.
  • A male hormone profile test via blood work in case the SA shows an abnormal outcome. It can help the urologist determine what is causing the results of the semen analysis to be abnormal.

Other male infertility tests that might be required are: a sperm DNA fragmentation test, sperm culture, karyotype testing, hypoosmotic swelling test, and testicular biopsy.

If you want to learn more about all the infertility tests available for males, visit the following article: What male infertility tests are available nowadays?

Reasons for infertility in males

Male sterility can be caused by a series of factors that can be classified into four groups:

Pre-testicular or endocrine causes
hormone imbalances affecting the development and/or the testicular function.
Testicular causes
when the cause of infertility can be found directly on the testes.
Post-testicular causes
problems with the ejection of sperm.
Sperm abnormalities
issues directly linked to the quality of the sperm produced.

In spite of the wide range of causes leading to male sterility, each one of them affects the quality of the ejaculated sperm to some extent. In order for a semen sample to have the adequate quality, parameters such as sperm concentration, sperm motility, sperm morphology, and sperm vitality should be within the normal values.

Pre-testicular or endocrine causes

This type of male infertility is caused by problems with the hormonal regulation of the male reproductive system, which alter the production of hormones by the pituitary gland. Some of these hormones are present in the development of the:

  • Testes
  • Seminiferous tubules
  • Spermatogenesis (i.e. production of sperm)
  • Development of the overall male reproductive system

The fact that the production of these hormones is altered causes the development or functioning of the testes to be compromised, which alters the production of spermatozoa.

Such issues might be caused by birth defects or external factors such as certain substances or drugs, e.g. anabolic steroids, that could cause the man to develop a hormone disorder, and therefore cause infertility. To determine the hormonal levels of males, a blood test is required.

Testicular causes

When we say testicular causes of male infertility, we refer to any factor affecting directly the testes. An alteration or defect in these reproductive organs can be congenital or acquired, that is, caused by external agents at any point in the patient’s life:

Congenital anomalies or abnormalities
Caused by genetic diseases, either by chromosomal conditions (i.e. the Klinefelter Syndrome), genetic causes, like the Noonan syndrome, or diseases caused by defects in the genes of the Y chromosome.
Acquired disorders
In this group, we find those problems caused as a side effect or adverse reaction of certain drugs or medical treatments, such as chemotherapy, drug consumption, or testicular trauma.

There exist different types of testicular trauma that can cause male infertility, including blunt, penetrating, or degloving (i.e. the scrotal skin is sheared off) lesions. They occur most often during contact sports.

Post-testicular causes

The post-testicular causes of male infertility comprise a set of complications derived either from a blockage or an abnormality in the seminal ducts. They are tubes or passages the sperms have to go through before being ejected after their production in the testes: the epididymis, the vasa deferentia (also known as ductus deferens), and the urethra.

Post-testicular alterations can be caused by an infection, blockage, or trauma. Being incapable of ejaculating is considered a post-testicular cause of male infertility as well.

Sperm abnormalities

Male infertility due to sperm abnormalities, that is, alterations in the sperm parameters is the leading cause of male infertility. This group includes those alterations in the sperms that affect directly their morphology, motility, vitality, or count. In order for the sperm quality to be evaluated, a semen analysis is the diagnostic test of choice, which allows the specialist to determine the presence of the following alterations:

Oligospermia or oligozoospermia
low sperm count, caused by varicocele, undescended testicle, orchitis, prostatitis, chemotherapy, etc.
issues with sperm motility.
Teratospermia or teratozoospermia
large amount of sperms with an abnormal morphology.
Necrospermia or necrozoospermia
large amount of dead sperms in the ejaculate.
zero sperm count.

Symptoms of infertility

In most cases, the man will not experience any obvious signs of infertility. More often than not, intercourse, erection and ejaculation occur without difficulty, and the quantity and appearance of the ejaculated semen appears to be normal. In short, male sterility can only be seen by means of the medical tests listed above.

In almost all cases, the only sign of male infertility is the inability to conceive a child after one year trying to conceive.

Other signs and symptoms commonly associated with male infertility include:

  • Pain, a lump, or swelling in the testicle area
  • Problems with sexual function, such as difficulties with ejection, reduced libido, erectile dysfunction, or small volumes of fluid ejaculated.
  • Gynecomastia (abnormal breast growth)
  • Having a lower-than-normal sperm count

Sometimes, an underlying problem such as an inherited disorder, dilated veins around the testicle, hormonal imbalances, or a condition that blocks the passage of sperm makes it visible to the naked eye, too.

Methods of treatment

When a couple is unable to conceive naturally and the cause is related to the male, fertility treatments can be the solution. By using one or a combination of the assisted reproductive technologies (ARTs) mentioned below, the pregnancy success rates range from 40 to 50% on average:

Intrauterine insemination (IUI)
Sperm are collected from the ejaculated semen, processed via sperm capacitation, and injected directly up into the female’s uterus.
In vitro fertilization (IVF)
Sperm are mixed with multiple eggs collected from the woman in a dish and the resulting embryos are placed in the uterus. For IVF to be successful, at least one viable sperm has to be found.
Intracytoplasmic sperm injection (ICSI)
While in IVF, the sperm fertilize the egg by themselves, in ICSI a single sperm is injected manually through a tiny needle into an egg. ICSI is recommended in cases of very low or abnormal sperm count.

If none of the fertility treatment options listed above work, sperm donation might be an option for the couple. Should you be interested in this form of third-party reproduction, visit the following guide: Having a baby using donated sperm.

If you need to undergo IVF to become a mother, we recommend that you generate your Fertility Report now. In 3 simple steps, it will show you a list of clinics that fit your preferences and meet our strict quality criteria. Moreover, you will receive a report via email with useful tips to visit a fertility clinic for the first time.

How common is infertility in men?

According to the US National Institute of Child Health and Human Development (NICHD), one-third of infertility cases are caused by male reproductive problems, one-third by female reproductive issues, and another one-third by both, or by unknown factors. Azoospermia, that is, a complete lack of sperm occurs in about 10% to 15% of infertile men.

The NICHD estimates that the major causes leading to male sterility are problems in the functionality of the testes, followed by hormone imbalances or blockages in the reproductive organs.

In general, global male infertility statistics show that infertility affects 15% of couples, which amounts to 48.5 million couples approximately. Males are found to contribute to 50% of cases overall, and are estimated to be responsible for 20-30% of infertility cases.

Male infertility rates are higher in Africa, Central Europe, and Eastern Europe. As for North America, Australia, and some regions of Central and Eastern Europe, the rate varies from 5-12%. Out of the cases of infertility in the USA, Latin America, and European countries, almost half of them are due to male factor.

FAQs from users

Why has sperm quality experienced such a dramatical decrease amongst males in the past few years?

By Emilio Gómez Sánchez BSc, PhD (senior embryologist).

A number of scientific studies suggest that sperm quality has decreased substantially in the past 50-80 years. For instance, a recent study indicates that, on average, the sperm count per ml is 52%, and the total amount of ejaculate is 59%.

These studies suggest that the decreased is more noticeable in industrialized countries.

Although the causes of this phenomenon are varied, it seems that the main reason can be found in the environment, and are endocrine disruptors. I am talking about chemical substances that simulate the effect of hormones by sending confusing signals to the organism, causing different dysfunctions, including a reduction in the sperm production process.

Endocrine disruptors are commonly found in consumer products, such as plastic, personal hygiene products, cleaning products, air fresheners… Also, many are present in foods.

Some examples of endocrine disruptors are dichlorodiphenyltrichloroethane (DDT), which was prohibited long time ago, bisphenol A, phthalate, styrene, certain solvents, resorcinol, etc.

Can HPV cause infertility in males?

By Zaira Salvador BSc, MSc (embryologist).

Some studies link the infection of semen with HPV to an impairment of sperm parameters, which suggests a potential role in male infertility, particularly in sperm motility. Also, it has been related to an increased risks of miscarriage among couples undergoing IVF, especially when HPV DNA was found in the semen sample of the male partner.

Can Chlamydia cause infertility in males?

By Zaira Salvador BSc, MSc (embryologist).

Yes, recent studies have shown that Chlamydia can harm the quality of the male sperm, as the degree of sperm fragmentation in these men’s sample is almost three times higher than in healthy males. Poor sperm motility, having defective shapes, or a low sperm count are the sperm parameters that could be affected by a Chlamydia infection.

Can infertility in males be cured?

By Zaira Salvador BSc, MSc (embryologist).

As long as male infertility is caused by a factor that can be cured, the answer is yes. However, it should be clear that infertility is not what can be cured, but the cause behind it. Blockages, toxic habits, treatments with reversible effects, etc. can be cured and the man recover his fertility. On the other hand, if the cause is unknown or irreversible (e.g. chemotherapy, congenital diseases…), there exists no cure.

Does testicular trauma affect fertility?

By Zaira Salvador BSc, MSc (embryologist).

Yes, although the long-term effects of testicular trauma on reproductive function remain still unknown. The most common consequence of testicular trauma in male fertility is testicular atrophy, which causes the testes to diminish is size and leads to a loss of function.

Can problems with sperm cause miscarriage?

By Zaira Salvador BSc, MSc (embryologist).

Yes. In cases where the father has a high incidence of abnormal chromosomes in his sperm, the risk of miscarriage is higher. Nevertheless, to date we still do not have any real percentages for how frequently the sperm is a factor leading to recurrent pregnancy loss.

Does sperm quality decrease as a man ages?

By Zaira Salvador BSc, MSc (embryologist).

Yes, the sperm quality of older men is lower than in young males. This decrease in fertility is not so significant as in females, though. From the age of 40 onwards, a man’s fertility starts diminishing. Investigations have shown that the sperm volume and the sperm count diminish as a man ages. The reduction occurs slowly, yet progressively. At the same time, the levels of oxidative stress tend to be higher.

The chances of the sperms developing some kind of genetic abnormality increase as well. However, a man can continue to be fertile, that is, capable of causing pregnancy in a fertile female at the age of 50, 60 or even 70. See also: Andropause or “male menopause”.

Can male infertility be cured with diet?

By Zaira Salvador BSc, MSc (embryologist).

A balanced diet, rich in antioxidants such as vitamin supplements or omega 3, can boost sperm quality in certain cases. However, improvement is not possible in the most severe cases of infertility. In such cases, fertility treatments are the only solution to achieve pregnancy. The following post may be of interest: Foods to boost sperm quality.

Are there any Ayurvedic treatments or remedies to cure male infertility?

By Zaira Salvador BSc, MSc (embryologist).

Ancient Ayurvedic treatments, home remedies, homeopathy medicine, or even acupuncture are said to be useful when it comes to treating male infertility. However, to date, there is no scientific proof that these “natural” remedies can actually cure or help to cure infertility in males.

Does mumps cause infertility in males?

By Zaira Salvador BSc, MSc (embryologist).

Childhood diseases such as mumps or chicken pox normally run their course and end without significant long-term effects. However, when a boy or an adult man contracts mumps, it can affect the testes and cause a condition called orchitis.

The prevalence of orchitis in young adults and adults ranges from 20% to 30%. Only in a small percentage of mumps-induced orchitis, the male experiences a reduction in sperm production, probably linked to changes in male hormones during the earliest stages of orchitis.

Are men with Cystic Fibrosis sterile by default?

By Zaira Salvador BSc, MSc (embryologist).

Most men with Cystic Fibrosis (CF) are infertile because of a blockage or absence of the sperm canal, an alteration known as congenital bilateral absence of the vas deferens (CBAVD). Since the sperm are unable to make it to the semen, it is impossible for them to reach and fertilize an egg with intercourse.

Suggested for you

If you want to learn about the most common causes of male infertility in detail, visit any of the following articles:

Do you need a fertility treatment to become parents but do not know how to get started? Then, do not miss our comprehensive guide to assisted reproduction techniques: Infertility treatments: definition and options available.

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Authors and contributors

 Zaira Salvador
BSc, MSc
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia (UPV). Embryologist specializing in Assisted Procreation, with a Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). More information
License: 3185-CV
 Emilio Gómez Sánchez
BSc, PhD
Senior Embryologist
Bachelor's Degree in Biology from the University of Seville. PhD in Biology from the University of Valencia. Large experience as an Embryologist Specialized in Assisted Reproduction. Currently, he is the IVF Lab Director of Tahe Fertilidad. More information
License: 14075-MU
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One comment

    1. diana

      Hello Sandra F… my husband is infertile, what are our options? Just wondering now on my own because I’m still young and would love to have children… if this is our situation, I’m considering the possibility of divorcing…