Different Forms And Causes Of Male Infertility

January 3, 2024
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Infertility is a common problem that most couples don’t consider until they experience it. Many factors cause and increase your risk of infertility and can harm your chances of getting pregnant.

An estimated 15% of American heterosexual couples encounter fertility issues when trying to conceive.1 Infertility is the inability to conceive after one year of frequent, unprotected sex.

It is difficult to determine how widespread male infertility is.2 Overall, about 8%-20% of infertility cases are caused by male reproductive factors, and in about 35% of cases, the cause is attributed to both male and female factors.3,4  In about 50% of cases, the cause of male infertility is unknown.5

Genetic Issues

Genetic changes in the DNA sequence of the male (Y) chromosome can cause infertility. Klinefelter’s syndrome (XXY) is an example. A genetic cause of infertility is suspected when a male has very small testes and very low to absent sperm count.

Other inherited conditions that can cause male infertility include: 6

  • Cystic fibrosis
  • Kallmann syndrome
  • Chromosomal abnormalities that affect testicular function
  • Small deletions of the genetic code on the Y chromosome

Underlying Medical Conditions

Diabetes, cancer, systemic infections, autoimmune disorders, celiac disease, cystic fibrosis, and medical conditions that cause increased oxidative stress can all contribute to male infertility.

Sexually transmitted infections that are undiagnosed and untreated can also contribute to male infertility. They can cause inflammation of the epididymis or testes and cause scarring.

Unhealthy Habits

Lifestyle factors can also contribute to male infertility, including:7

  • Obesity is associated with decreased testosterone and reduced sperm counts. Researchers found that people who engage in regular, moderate levels of exercise and choose a healthy diet comprising whole foods are less likely to have infertility.
  • Illicit substance use can also affect sperm function. Marijuana directly affects sperm function by acting on the cannabinoid receptors.
  • Tobacco use is associated with decreased semen volume, sperm count, and sperm motility. Toxins found in cigarette smoke and nicotine are both thought to impact fertility.
  • Excessive alcohol consumption causes decreased testosterone levels and impacts all aspects of sperm function. Binge drinking, especially, should be avoided.

Physical Trauma/Surgical Side Effects

Injury, physical trauma, and surgical complications can also cause male infertility if they affect how sperm are produced and transported through the male reproductive system. Severe testicular trauma or scar tissue in any of the ducts can prevent sperm from passing through the male reproductive tract.

Excessive heat exposure can also cause male infertility. Potential causes include wearing tight underwear, placing a laptop on your lap, an undetected varicocele, or frequent hot tub or sauna use.

A couple looking at male infertility test results

Ejaculation Issues

With ejaculation, sperm in semen is forcefully expelled from the vas deferens, through the ejaculatory duct, and out the urethra. With retrograde ejaculation, the muscle that keeps ejaculate from passing backward into the bladder fails to contract, and semen passes into the bladder instead of out the penis through the urethra.

Besides infertility, another clue that a man has retrograde ejaculation is a cloudy appearance to his urine right after sex. This is because the urine contains sperm.

Undescended Testicles

The testes move from the abdominal cavity into the scrotum during fetal development. If they remain in the abdomen and do not fully descend into the testes, this increases the risk of poor sperm quality. The longer the testes remain undescended, the greater the risk to future fertility.

Typically, undescended testes are detected during well-child exams during the first year of life. Surgical repair of undescended testes is usually recommended before age one year. Early surgical intervention can reverse some of the hormonal, genetic, and developmental abnormalities associated with undescended testes.8

Tubular Defects

Sperm must pass from the testes, where they are produced, through the epididymis, where they are stored until they mature. With ejaculation, sperm are forcefully expelled from the epididymis into the vas deferens through the ejaculatory duct, leaving the penis after traveling the length of the urethra.

Abnormalities, narrowing, or scarring along these ducts can cause infertility.

Hormonal Disorders

Genetic predisposition, medical conditions, medications, and aging are a few factors that can affect your hormone levels. Endocrine organs and the hormones they produce have widespread effects. Abnormalities of the hypothalamus, pituitary, thyroid, and adrenal glands can cause male infertility.

To naturally regulate your hormones:

  • Get 7 to 9 hours of restful sleep
  • Do regular strength-building exercises
  • Watch your weight
  • Address your stress
  • Avoid environmental toxins
  • Consume a nutritious diet

Physical, psychological, and sexual health are all intertwined. Decreased libido and erectile dysfunction, or other conditions that interfere with sex, can cause infertility. If making lifestyle changes does not improve your sexual health, talk to an Invigor Medical treatment specialist to learn more about prescription sexual-health treatments such as:

  • Passion: improves mood, erectile function, and libido and fosters intimacy
  • PT-141: improves libido and erectile function
  • Tadalafil-Oxytocin: increases libido and erectile function

Aging (over age 40-45) is a risk factor for hormonal disorders and infertility. Male aging is associated with a decrease in sperm count and motility.9 After receiving a complete physical exam, talk to your doctor about options for age management.

Different Forms And Causes Of Male Infertility

Anti-Sperm Antibodies

Sperm are normally protected from the immune system. When these barriers are breached, the immune system can form antibodies to sperm because they are genetically different from body cells.

Anti-sperm antibodies are immune cells that bind to sperm cells and can cause clumping. Many men have anti-sperm antibodies, but they do not cause infertility. Anti-sperm antibodies are suspected of causing infertility when sperm show slow motility and are clumped together in a semen sample.

When anti-sperm antibodies cause infertility, sperm washing followed by in-vitro fertilization is one treatment option. Using corticosteroids to decrease the immune response is another.10

testosterone test

Cancer Treatments/Tumors

Cancers and nonmalignant tumors that directly affect the male reproductive system or organs that release hormones, such as the pituitary gland, can affect fertility. Chemotherapy or radiation treatment used to treat cancers can also cause male infertility.

Medication Side Effects

Some medications can cause infertility by affecting hormone production or sexual function.

  • Anabolic steroids: testosterone and its synthetic derivatives are used by some people to increase muscle mass and decrease body fat. These medications blunt natural testosterone production.11 In one study, bodybuilders had significantly reduced percentages of normal, motile sperm when compared to healthy volunteers.12
  • Antidepressants: these medications can decrease sperm concentration and motility, increase DNA fragmentation, and decrease reproductive organ weights.13
  • Other medications: some chemotherapeutic drugs and medications used to treat arthritis or ulcers can impair sperm production and decrease male fertility. Cannabinoids, opioids, and psychotropic drugs can inhibit gonadotropin-releasing hormone, which affects sperm production and maturation.8

Malformed Sperm

Malformed sperm typically cannot survive the long trip from the male reproductive system through the female reproductive system to fertilize an egg.


Azoospermia is the inability to produce sperm.


Globally, sperm counts have decreased over recent decades. The mean sperm count has declined by 51.6% between 1973 and 2018. The rate of decline increased after 2000, from 1.16% per year to 2.64%.14

The exact cause of a global decline in sperm count is not fully understood but may be due to long-term exposure to environmental toxins such as pesticides, plasticizers, and radiation.8


Varicoceles are the most common cause of male infertility. Almost 15% of men and 40% of men with infertility have varicoceles, which are swollen veins.15 How varicoceles are related to infertility is not fully understood, but it may be due to blood reflux or a temperature change. Varicoceles can cause reduced sperm quality and quantity.

Ideally, sperm production occurs at around 93.2ºF. When blood vessels around the testes are enlarged, temperature may increase slightly, impacting testosterone levels and sperm production. If a varicocele is noted on a physical exam, it may be repaired surgically or using a percutaneous embolization technique. Varicocele repair has a low risk of complications, and in most cases, semen quality and fertility improve in 3 to 6 months.15

Author: Leann Poston, M.D.
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