Everything you need to know about male fertility — sperm parameters, causes of low count, and how to improve results — with expert top 5 picks for at-home sperm tests.
Male infertility contributes to roughly half of all couples’ difficulty conceiving. It’s most often caused by low sperm count, poor motility, or abnormal morphology. Home testing now allows private, early screening.
Male factor infertility contributes to approximately 50% of all infertility cases — yet male fertility is tested far less frequently and discussed far less openly than female fertility. A semen analysis is the cornerstone of male fertility evaluation, measuring sperm count, motility (movement), and morphology (shape). At-home male fertility tests now provide a private, accessible first step for men who want to understand their fertility status before or during the conception journey.
The World Health Organization (WHO) defines normal semen parameters as: sperm concentration ≥16 million/mL, total motility ≥42%, progressive motility ≥30%, and normal morphology ≥4% (Kruger strict criteria). These thresholds represent the lower reference limit in fertile men — not an optimum target.
When to get tested: If you and your partner have been trying to conceive for 12 months without success (6 months if she is over 35), a semen analysis should be among the first tests done — it's non-invasive, relatively inexpensive, and immediately informative. Don't wait to test the female partner exclusively.
| Parameter | Lower Reference Limit | What It Means | If Below Normal |
|---|---|---|---|
| Sperm Concentration | 16 million/mL | Number of sperm per milliliter of semen | Oligospermia — low sperm count |
| Total Sperm Count | 39 million/ejaculate | Total number of sperm in the sample | Low total output — volume issue possible |
| Total Motility | 42% | Percentage of sperm that are moving | Asthenospermia — poor sperm movement |
| Progressive Motility | 30% | Percentage moving forward purposefully | Poor forward progression — IUI/IVF may be needed |
| Normal Morphology | 4% | Percentage with normal shape | Teratospermia — abnormal shape affects fertilization |
Enlarged veins in the scrotum — most common surgically correctable cause of male infertility, affecting 40% of infertile men
Low testosterone, high FSH/LH, thyroid dysfunction, and prolactin elevation all impair sperm production
Sperm production requires temperatures 2–4°C below body temperature — laptops, hot tubs, tight underwear, and occupational heat reduce count
Smoking reduces sperm count by 22%, alcohol impairs testosterone, cannabis reduces motility, anabolic steroids suppress sperm production entirely
STIs (especially chlamydia, gonorrhea), epididymitis, and orchitis can cause scarring that blocks sperm transport
High sperm DNA fragmentation (>25%) causes recurrent miscarriage and IVF failure even with normal standard semen parameters
Retrograde ejaculation, obstruction, or congenital absence of the vas deferens — structural causes requiring specialist evaluation
Sperm DNA fragmentation increases significantly after age 45; older paternal age is linked to higher rates of de novo genetic mutations in offspring
Keep laptops off the lap, avoid hot tubs and saunas during conception attempts, switch to looser underwear. Sperm take 72 days to mature — changes take 3 months to reflect in test results.
Oxidative stress damages sperm DNA. Mediterranean diet rich in zinc (oysters, beef), selenium (Brazil nuts), folate (leafy greens), vitamin C and E reduces DNA fragmentation.
Smoking reduces count by 22% and motility by 13%. Alcohol above 5 drinks/week significantly impairs testosterone and morphology. Both effects reverse within 3 months of cessation.
CoQ10 (200–600mg) — strongest evidence for improving motility. Zinc (25–45mg). Folate + B12. Vitamin D. Ashwagandha — shown to increase sperm count by 167% and motility by 57% in one RCT.
Moderate exercise raises testosterone and improves sperm parameters. Excessive endurance training can suppress testosterone. Anabolic steroids completely shut down sperm production.
Testosterone is produced during sleep — less than 7 hours reduces levels by up to 15%. Chronic stress elevates cortisol which suppresses testosterone and sperm production.
| Treatment | Indication | Success Rate | Notes |
|---|---|---|---|
| Varicocelectomy | Varicocele + abnormal semen | 40–60% natural conception | Surgery or microsurgical — significant improvement in parameters |
| Hormonal therapy | Hypogonadotropic hypogonadism | High (if hormonal cause) | hCG, FSH injections stimulate sperm production |
| Intrauterine Insemination (IUI) | Mild male factor | 10–20% per cycle | Washed sperm placed directly in uterus |
| IVF + ICSI | Severe male factor | 40–50% per cycle (age dependent) | Single sperm injected directly into egg — bypasses most male factor issues |
| Sperm Retrieval (TESA/PESA) | Azoospermia (no sperm in ejaculate) | Depends on cause | Sperm extracted directly from testis or epididymis |
#1 Pick: Legacy Male Fertility Test (At-Home + Lab) · Score: 9.7/10 · 5 products tested
Sperm take approximately 72–74 days to mature (spermatogenesis). This means any lifestyle change — quitting smoking, starting supplements, reducing heat exposure — takes at least 3 months to show up in test results. Test before starting an intervention, then retest at 3 months to measure the change. Don't test sooner — the results won't yet reflect your changes.
Device-based home tests (YO, Trak, ExSeed) measure sperm concentration and motility — the two most important parameters — but cannot measure morphology (shape) or DNA fragmentation, which require laboratory microscopy. Lab-send tests (Legacy, Fellow) provide full clinical semen analysis including morphology. For a complete fertility evaluation, a lab-send test or clinical semen analysis is needed. Home device tests are valuable for initial screening and ongoing monitoring.
Yes — significantly. Exogenous testosterone (from anabolic steroids or testosterone replacement therapy) suppresses the hypothalamic-pituitary-gonadal axis, shutting down the body's own testosterone production and sperm production via negative feedback. Many men on TRT have zero sperm in their ejaculate (azoospermia). This is often reversible after stopping TRT, but recovery can take 6–18 months and is not guaranteed, especially with long-term use. If you want children, discuss fertility preservation with a urologist before starting TRT.
Sperm DNA fragmentation refers to breaks or damage in the genetic material within sperm. A DNA fragmentation index (DFI) above 15% is associated with reduced natural conception rates; above 25% is associated with recurrent miscarriage and IVF failure even when other semen parameters appear normal. Standard semen analysis does not measure DNA fragmentation — it requires a separate TUNEL, SCSA, or SCD test. Legacy's lab-send test includes DNA fragmentation, making it uniquely valuable for couples with recurrent miscarriage or failed IVF cycles.
For both home and clinical tests: abstain from ejaculation for 2–5 days before testing (2–3 days is optimal — less reduces count, more reduces motility); avoid alcohol for 5 days prior; avoid hot tubs, saunas, and excess heat for 2 weeks prior; avoid fever-causing illness in the past 6 weeks (illness temporarily reduces count for 3 months); collect the complete sample without losing any portion. For lab-send tests, check that you can get the sample to the lab within the required time window.
Every Tuesday we send you the single most useful review we published that week. No spam, no affiliate pitches, no clickbait — just the work.