Male Infertility: Causes, Tests, and What Your Results Mean

When a couple has been trying to conceive for a year without success, the workup should always include the man from the start. Yet studies from multiple countries show that in more than half of couples reaching a fertility clinic, the male partner has never had even a single semen analysis. This is a mistake that costs time, money, and sometimes the chance of natural conception.

This guide, written by a practising Istanbul urologist and andrologist, explains what causes male infertility, what tests are done, and — critically — what the numbers on the report actually mean. It is written for men and couples navigating an infertility workup for the first time.

What counts as male infertility?

Kısırlık is the inability of a couple to conceive after 12 months of regular, unprotected intercourse (6 months if the female partner is over 35). Male infertility is diagnosed when the male partner has an identifiable factor — an abnormal semen analysis, hormonal derangement, genetic abnormality, or structural problem — contributing to that failure.

The full staircase of options — from tablets to injections to prosthesis — is mapped on our erectile dysfunction treatment overview.

Importantly, “male factor” is not always the sole factor. Roughly 20% of infertility is purely male, another 20–30% is combined (male + female), and about 10–15% remains unexplained even after full evaluation of both partners.

How common is a male factor?

Meta-analyses and WHO data converge on similar numbers:

A non-drug option that some men trial first is low-intensity shockwave therapy for ED.

• A male factor is involved in approximately 40–50% of infertile couples.
• Sperm concentration in the general population has declined ~50% over the past four decades in Western studies (Levine et al.), a trend seen across most regions.
• About 1% of all men and 10–15% of infertile men have azoospermia — no sperm in the ejaculate.

The clinical implication: any couple starting a fertility investigation must have the man evaluated in parallel with the woman, not months later after IUI or IVF has already been attempted.

The main causes of male infertility

Grouped by mechanism:

Regenerative medicine adds a further tier: stem cell therapy for erectile dysfunction.

Anabolic steroid and exogenous testosterone use deserves special mention: it is a rapidly growing cause of azoospermia in men under 40. Long-acting testosterone or SARMs shut down the pituitary–testis axis and can suppress sperm production for 6–18 months after cessation.

History and physical exam

A proper first consultation covers:

• Duration of trying to conceive; frequency and timing of intercourse
• Prior pregnancies (with current or previous partners)
• Childhood surgery (hernia, hydrocele, undescended testis)
• Puberty timing, testicular trauma, mumps orchitis, torsion history
• Sexually transmitted infections, urinary infections
• Medications (testosterone, finasteride, chemotherapy, opioids, SSRIs)
• Recreational drug and anabolic steroid use
• Occupational exposure (heat, pesticides, solvents)
• Family history of infertility, cystic fibrosis, or genetic disease

Physical examination assesses testicular volume (normal 15–25 mL by orchidometer), consistency, presence of both vasa deferentia, epididymal swelling, varicocele on Valsalva, and secondary sex characteristics.

Semen analysis — WHO 2021 values

Semen analysis is the cornerstone. It should be done at least twice, 2–3 weeks apart, after 2–7 days of ejaculatory abstinence. Reference values from WHO 2021 (6th edition) — the current international standard:

The newer, cell-free regenerative sibling of stem cell work is exosome therapy for erectile dysfunction.

Important nuance: these are reference limits, not thresholds for fertility. A man below cutoff can still father a child; a man above cutoff can still be subfertile. That is why the analysis is interpreted alongside the couple’s whole picture.

Common patterns:

• Oligozoospermia — sperm concentration <16 million/mL
• Asthenozoospermia — progressive motility <30%
• Teratozoospermia — normal morphology <4%
• Oligoasthenoteratozoospermia (OAT) — all three abnormal (classic “varicocele stress pattern”)
• Azoospermia — no sperm found after centrifugation
• Cryptozoospermia — sperm found only after centrifugation

Hormone panel — FSH, LH, testosterone, prolactin

A basic andrology hormone panel includes:

Anatomical length or girth is a separate procedure — details on our penis enlargement surgery page.

• FSH — reflects Sertoli cell function and spermatogenesis. High FSH (>10 IU/L) with small testes and azoospermia suggests non-obstructive azoospermia.
• LH — pituitary drive to Leydig cells
• Total testosterone — early morning, fasting; repeated on a second day if low
• Prolactin — elevation (>20 ng/mL) can suppress the HPG axis and warrants pituitary MRI
• TSH — screening for thyroid disease
• Oestradiol — helpful when testosterone is low or when obesity is present

Interpretation patterns:

Scrotal and transrectal ultrasound

Scrotal Doppler ultrasound is the imaging workhorse. It confirms varicocele (reflux >2 s on Valsalva), measures testicular volume, and detects hydroceles, cysts, and — critically — testicular tumours, which are 20-times more common in infertile men.

Transrectal ultrasound (TRUS) is reserved for suspected ejaculatory duct obstruction: low semen volume (<1.5 mL), low pH, absent fructose, and azoospermia with normal testes and normal FSH. TRUS looks for midline prostatic cysts and dilated seminal vesicles.

Genetic testing — karyotype, Y-microdeletion, CFTR

Genetic testing is recommended when:

A common, surgically-treatable cause is discussed in varicocele symptoms and treatment.

• Sperm concentration is <5 million/mL (severe oligozoospermia)
• Azoospermia (any type)
• Congenital bilateral absence of the vas deferens (CBAVD)
• Recurrent pregnancy loss with the same partner

The three main tests:

• Karyotype — detects chromosomal abnormalities. Klinefelter syndrome (47,XXY) is found in ~10% of azoospermic men.
• Y-chromosome microdeletion — assays for deletions in the AZFa, AZFb, and AZFc regions. AZFa or AZFb deletions predict no sperm retrieval; AZFc offers reasonable retrieval rates.
• CFTR mutation panel — mandatory in CBAVD, since ~80% carry at least one CFTR mutation. Genetic counselling for the couple is essential before ICSI.

Sperm DNA fragmentation

Sperm DNA fragmentation index (DFI) quantifies the proportion of sperm carrying damaged DNA. Elevated DFI (>25–30% depending on assay) is associated with:

For a topline summary, read common causes of male infertility.

• Recurrent early pregnancy loss
• Poor embryo development in IVF
• Failed ICSI cycles despite morphologically normal embryos
• Longer time to natural conception

Drivers of high DFI include varicocele, infection, smoking, obesity, advanced paternal age, environmental heat, and oxidative stress. DFI often improves after varicocele repair, antioxidant therapy, and lifestyle changes over 3–6 months.

Azoospermia — obstructive vs non-obstructive

The critical fork in the road for men with no sperm in the ejaculate:

MicroTESE (microsurgical testicular sperm extraction) is the gold-standard sperm retrieval technique for non-obstructive azoospermia. Under high-magnification microscopy, individual seminiferous tubules are examined and the largest, most opaque tubules are sampled — dramatically improving yield versus conventional TESE and minimising loss of functional testicular tissue.

How to interpret your report

A few practical rules:

The mental-health side is under-discussed — see the emotional impact of male infertility.

• Never treat one bad semen sample as a diagnosis. Repeat after 2–3 weeks. Volatility is real — a fever, an antibiotic, or a stressful week can move numbers.
• Look at the whole pattern, not one number. Isolated low morphology with everything else normal rarely explains infertility on its own.
• Correlate with the hormones and the physical exam. A single semen number in isolation misleads.
• Check DNA fragmentation when repeated IVF or ICSI has failed with a woman who has an otherwise normal workup.
• Ask about total motile sperm count (concentration × volume × motility) — a stronger fertility predictor than any single value.

Next steps after a diagnosis

Options depend on the finding:

If a diagnosis is missing, start with the 12 medical causes of erectile dysfunction.

• Varicocele + abnormal semen: consider microsurgical varicocelectomy
• Endocrine cause (hypogonadotropic hypogonadism): gonadotropin therapy (hCG ± FSH) or clomiphene
• Obstructive azoospermia: vasovasostomy or vasoepididymostomy where feasible; otherwise sperm retrieval + ICSI
• Non-obstructive azoospermia: optimise hormones, treat varicocele where present, then microTESE + ICSI
• Idiopathic oligozoospermia: lifestyle optimisation, antioxidant therapy, IUI or ICSI depending on total motile count
• Elevated DFI: treat cause, antioxidants, consider testicular sperm for ICSI

Doctor’s perspective — Op. Dr. Cem İpek

The most avoidable pattern I see is a couple two years into IVF cycles where the husband has never seen a urologist. In perhaps a third of these men there is a treatable finding — a varicocele, an untreated infection, exogenous testosterone use, high DFI, or a hormonal issue — that could have shifted the entire treatment plan.

Numbers on a semen analysis are important, but they are probabilistic, not deterministic. I have seen men with counts under 5 million/mL conceive naturally, and I have seen men with textbook-normal reports remain infertile for years. This is why we treat the couple, not the number.

For azoospermic men, the conversation used to end with a shrug. Today, with microTESE and ICSI, roughly half of men with non-obstructive azoospermia can father a genetically related child. Even Klinefelter syndrome — long considered hopeless — has sperm retrieval rates of about 40–50% in experienced hands.

When to see a urologist

Book an appointment if any of the following applies:

• Trying to conceive for >12 months (or >6 months if the female partner is >35)
• Any abnormal semen analysis, even a single one
• History of undescended testis, testicular torsion, mumps orchitis, or hernia repair
• History of chemotherapy, radiotherapy, or pelvic surgery
• Current or recent use of testosterone, SARMs, or anabolic steroids
• Low libido, small testes, or gynaecomastia
• Recurrent pregnancy loss
• Failed IUI or IVF cycles

Frequently asked questions