Male Infertility Causes — the Complete Guide
Male factors contribute to roughly 40–50% of all infertility — but they get roughly 10% of the attention, 5% of the conversation, and often zero testing until the female partner has been through months of invasive workups. A semen analysis costs a few hundred rupees and takes one visit. It should always be the first test. Read our semen analysis guide if you haven’t already.
The Major Categories
Production Problems — Not Enough Sperm, or None
Varicocele is the most common identifiable cause — enlarged veins in the scrotum overheat the testes and impair production. Found in up to 40% of men with fertility problems, it’s diagnosed by physical examination and confirmed by ultrasound. Surgical repair (varicocelectomy) is a minor procedure that improves parameters in about two-thirds of men within 3–6 months — sometimes enough to conceive naturally or shift from IVF to IUI.
Hormonal imbalance — low FSH, low testosterone signalling, elevated prolactin, thyroid disorders — suppresses production. Simple blood tests identify these, and medication often restores output. Critically: testosterone replacement therapy (TRT) given for “low T” in gyms and wellness clinics shuts down sperm production. If you’re on TRT and trying to conceive, tell your fertility doctor immediately — it’s reversible but takes months.
Genetic causes — Y-microdeletions, Klinefelter syndrome (47,XXY), and other chromosomal issues can severely reduce or eliminate production. Where suspected, genetic testing and counselling before treatment are important, because some conditions can pass to sons conceived via ICSI.
Cryptorchidism (undescended testes in childhood), past chemotherapy or radiation, mumps orchitis, and testicular trauma all carry long-term production consequences — another reason medical history matters in the fertility consultation.
Delivery Problems — Sperm Made but Can’t Get Out
Obstructive azoospermia: normal production, blocked pathway — from prior infection (including STIs), surgery (hernia repair, vasectomy), or congenital absence of the vas deferens (often linked to cystic fibrosis gene mutations). Sperm can frequently be retrieved surgically (PESA, TESA) and used with ICSI — the production factory is working; the delivery truck is broken.
Retrograde ejaculation: semen goes backward into the bladder instead of out. Caused by diabetes, medications, or prostate surgery. Sperm can often be recovered from urine and used for IUI or IVF.
Erectile dysfunction: an underestimated cause — if intercourse doesn’t happen at the right time, everything else is moot. Medical treatment (sildenafil, tadalafil) resolves most cases; for persistent ED, sperm collection by other methods plus IUI or IVF bypasses the issue entirely.
Quality Problems — Sperm Present but Damaged
Sperm DNA fragmentation: the sperm looks normal under the microscope but carries broken DNA, leading to fertilisation failure, poor embryo development, or early miscarriage. Causes include oxidative stress, varicocele, infection, and lifestyle factors. Specialised testing (TUNEL, SCD, SCSA) measures this when standard analysis is normal but outcomes are poor.
Antisperm antibodies: the immune system targets its own sperm — usually after vasectomy reversal or testicular trauma. ICSI bypasses this completely.
Lifestyle and Environment
Smoking, heavy alcohol, obesity, chronic stress, heat exposure (saunas, tight underwear, laptop on lap), and certain medications (SSRIs, calcium channel blockers, anabolic steroids) all measurably impair sperm. The good news: sperm regenerates every ~72 days. The 10-week improvement project addresses every modifiable factor, and repeat analysis afterward often shows real change.
The Investigation Pathway
Step 1: Semen analysis — repeat if abnormal. Step 2: Hormone panel (FSH, LH, testosterone, prolactin, thyroid). Step 3: Physical examination (varicocele, testicular size). Step 4: Scrotal ultrasound if indicated. Step 5: Genetic testing if count is very low or zero. Step 6: DNA fragmentation testing if standard results are normal but fertility outcomes are poor.
Most diagnoses have a clear treatment path — from lifestyle correction to medication to varicocele repair to surgical retrieval with ICSI. The tragedy is only in never testing. Read our male infertility treatment overview or ask Pregology for guidance.