Male Infertility: Signs, Causes and When to Get Tested

Signs of male infertility

Most infertile men feel well and have normal sex lives. Possible clues:

• difficulty conceiving despite regular unprotected sex for a year
• sexual problems: low libido, erectile dysfunction, trouble ejaculating, or very little fluid
• dry orgasm or cloudy urine after orgasm: retrograde ejaculation into the bladder
• pain, swelling or a lump in the scrotum
• small, soft testicles
• reduced facial or body hair, breast enlargement or other signs of low testosterone
• repeated chest infections or a poor sense of smell, linked to rare genetic conditions

Causes

Sperm production problems (most common)

• Varicocele: enlarged veins in the scrotum that overheat the testicle. Found in about 15 percent of all men and about 35 to 40 percent of men with infertility.
• Undescended testicles in childhood, even if corrected.
• Infection or inflammation: mumps orchitis after puberty, sexually transmitted infections.
• Genetic conditions: Klinefelter syndrome (XXY), Y-chromosome microdeletions.
• Cancer treatment: chemotherapy and radiotherapy, and testicular cancer itself.
• Unexplained: in many men no single cause is found.

Hormone problems

• Low testosterone and hypogonadism from pituitary or testicular problems
• high prolactin from a pituitary tumor
• thyroid disease
• testosterone or anabolic steroid use, which switches off the body's own sperm production. This is a common and reversible cause

Blockage or delivery problems

• missing vas deferens (associated with cystic fibrosis gene mutations)
• blockage after infection, hernia surgery or vasectomy
• retrograde ejaculation after prostate surgery, from diabetes or some medicines
• erection and ejaculation problems

Lifestyle and environmental factors

• smoking, heavy alcohol use, cannabis and other drugs
• obesity
• heat exposure: hot tubs, saunas, laptops on the lap
• some medicines: certain blood pressure drugs, opioids, sulfasalazine, finasteride (in some men)
• pesticides, heavy metals and solvents at work
• age: sperm quality slowly declines after about 40

How male infertility is tested

Semen analysis

The key test. You produce a sample by masturbation after 2 to 5 days without ejaculation, and the lab measures:

Results vary a lot between samples, so an abnormal result is repeated at least once, a few weeks later. Values below these limits mean reduced fertility, not that pregnancy is impossible.

Other tests

• physical exam of the testicles, vas deferens and veins
• hormone tests: testosterone, FSH, LH, prolactin
• genetic tests (karyotype, Y-chromosome microdeletions, cystic fibrosis genes) for very low or absent sperm
• scrotal ultrasound
• post-ejaculation urine test for retrograde ejaculation
• sperm DNA fragmentation testing in some cases

The female partner should be assessed at the same time, since both partners often have contributing factors. See male factor infertility for diagnosis and treatment in more depth.

Treatment

• Lifestyle: stop smoking, cut alcohol, lose excess weight, avoid heat to the scrotum. Sperm take about 2 to 3 months to develop, so changes take that long to show.
• Stop testosterone or steroids under medical supervision; recovery can take months.
• Varicocele repair can improve semen quality in men with an abnormal semen analysis and a palpable varicocele.
• Medicines for hormone problems, such as gonadotropins for pituitary causes.
• Treat infections and retrograde ejaculation.
• Surgery to reverse a vasectomy or bypass a blockage.
• Sperm retrieval directly from the testicle when no sperm are in the ejaculate.
• Assisted reproduction: intrauterine insemination (IUI) for mild problems, and IVF with intracytoplasmic sperm injection (ICSI), where a single sperm is injected into each egg, for more severe problems.

Men facing cancer treatment should be offered sperm banking beforehand.

Male infertility and overall health

Male infertility can be the first sign of another condition, such as a hormone disorder, genetic condition or, rarely, testicular cancer. Men with abnormal semen analysis have higher rates of some health problems, so a full medical evaluation is worthwhile.

Frequently asked questions

What are the signs of male infertility?

Most men have no signs other than difficulty conceiving. Some notice low sex drive, erection or ejaculation problems, a lump, pain or swelling in the scrotum, small testicles, or reduced facial and body hair. A semen analysis is the only way to know.

What is the most common cause of male infertility?

Problems with sperm production are the most common, and varicocele is the most common correctable cause. Hormone problems, blockages, genetic conditions, testosterone use and lifestyle factors such as smoking and obesity also contribute. In many men, no specific cause is found.

Can male infertility be cured?

Sometimes. Stopping steroid use, repairing a varicocele, treating hormone problems or reversing a blockage can restore natural fertility. When it cannot be corrected, IVF with ICSI allows many men to father biological children, even with very low sperm counts.

Does taking testosterone cause infertility?

Yes. Testosterone and anabolic steroids signal the brain to stop making the hormones that drive sperm production, often reducing sperm to very low levels or zero. Production usually recovers after stopping, but it can take many months.

How long should we try before getting tested?

See a doctor after 12 months of regular unprotected sex without pregnancy, or after 6 months if the female partner is 35 or older. Men with known risk factors, such as past undescended testicles or cancer treatment, should be tested earlier.