There’s no single symptom that tells you you’re infertile. Most men with fertility problems have no obvious signs at all. The only reliable way to know is through a semen analysis, a lab test that measures sperm count, movement, and shape. But there are physical clues, lifestyle risks, and a clear diagnostic path worth understanding before and after that test.
Male factors are solely responsible for an estimated 20 to 30 percent of all infertility cases, and contribute to roughly half when combined with female factors. If you’ve been trying to conceive without success, the odds that something on your side needs investigating are real.
Physical Signs Worth Paying Attention To
Most men with low sperm counts feel completely normal. That said, certain physical changes can point toward a hormonal or structural problem affecting fertility:
- Low ejaculate volume or difficulty with ejaculation
- Reduced sex drive or trouble maintaining erections
- Pain, swelling, or a lump near the testicles
- Unusual breast tissue growth, sometimes called gynecomastia
- Decreased facial or body hair, which can signal a hormonal or chromosomal issue
None of these guarantee infertility, and their absence doesn’t guarantee fertility. But if you notice any of them alongside difficulty conceiving, they’re worth mentioning to a doctor because they help narrow down the cause.
When to Get Tested
The general guideline is to seek evaluation after 12 months of regular, unprotected intercourse without a pregnancy. That timeline shortens to six months if your female partner is between 35 and 40, and evaluation should happen immediately if she’s over 40 or has known risk factors like previous pelvic inflammatory disease or tubal problems.
You don’t have to wait for those timelines if you already suspect a problem. A history of undescended testicles, groin surgery, chemotherapy, or known hormonal issues is reason enough to get tested early.
What a Semen Analysis Measures
A semen analysis is the cornerstone test. You provide a sample (usually through masturbation at a clinic or at home with a collection kit), and a lab evaluates several parameters. The current reference values, set by the World Health Organization in 2021, define the lower limits of normal:
- Semen volume: at least 1.4 mL per ejaculate
- Total sperm count: at least 39 million per ejaculate
- Sperm concentration: at least 16 million per milliliter
- Total motility (sperm that move at all): at least 42%
- Progressive motility (sperm swimming forward): at least 30%
- Normal morphology (properly shaped sperm): at least 4%
Falling below one or more of these thresholds doesn’t mean pregnancy is impossible. These are 5th-percentile values, meaning 95% of men who recently fathered a child scored above them. Results below these numbers indicate reduced fertility, not zero fertility. Doctors typically want at least two analyses, spaced a few weeks apart, before drawing firm conclusions, since sperm production fluctuates.
At-Home Sperm Tests: How Reliable Are They?
Several smartphone-based and mail-in kits now let you check sperm concentration and motility without visiting a clinic. One well-studied device showed 97.8% accuracy when compared to a professional lab analyzer, with the ability to reliably distinguish between low and normal motile sperm concentrations. That’s genuinely useful as a screening tool.
The limitation is scope. Home tests typically measure one or two parameters. They won’t assess morphology, white blood cell counts, or semen volume with the same precision a lab provides. Think of them as a reasonable first step. If a home test comes back low, you’ll still need a full lab analysis. If it comes back normal, it’s reassuring but not a complete picture.
Varicoceles: The Most Common Treatable Cause
A varicocele is an enlargement of the veins inside the scrotum, similar to a varicose vein in the leg. It’s the most frequently identified correctable cause of male infertility. You might notice one side of your scrotum looks larger or feels like a “bag of worms” when you stand. Sometimes there’s a dull ache that worsens after standing for long periods.
Varicoceles damage sperm production through several mechanisms. The enlarged veins pool blood and disrupt the temperature regulation system that keeps the testicles cooler than the rest of the body. The resulting heat stress harms developing sperm. At the same time, increased venous pressure triggers the small arteries feeding the testicle to constrict, reducing oxygen and nutrient delivery to the cells that produce sperm. Oxidative stress and hormonal imbalances add further damage.
They occur more often on the left side due to the way the left testicular vein drains into the kidney vein at an angle that increases pressure. Many varicoceles are detectable through a simple physical exam. Surgical repair or a minimally invasive procedure to redirect blood flow often improves sperm parameters over the following months.
Hormonal and Genetic Testing
If a semen analysis shows very low or absent sperm, your doctor will likely check hormone levels, particularly testosterone and follicle-stimulating hormone. These results help distinguish between a production problem in the testicles and a signaling problem from the brain’s pituitary gland.
Genetic testing enters the picture when sperm counts are severely low or sperm are completely absent (azoospermia). The most common genetic tests look for Y-chromosome microdeletions, which are tiny missing segments on the Y chromosome that affect sperm production genes. Karyotype analysis checks for broader chromosomal abnormalities like Klinefelter syndrome, where a man carries an extra X chromosome. These results don’t just explain the cause; they help predict whether sperm retrieval procedures are likely to succeed and whether genetic conditions could be passed to children.
Lifestyle Factors That Affect Sperm Quality
Sperm take roughly 74 days to develop, which means lifestyle changes you make today won’t show up in a semen analysis for about three months. The flip side is encouraging: if you address modifiable risk factors now, you may see measurable improvement.
Smoking has a clear impact. Among otherwise healthy men, smokers have roughly 13 to 24% lower sperm concentration compared to nonsmokers. Excess weight also plays a role. Overweight men tend to have lower sperm concentration and total sperm counts than those at a healthy weight, likely due to hormonal shifts involving estrogen and testosterone balance, along with increased scrotal temperature from excess tissue.
Heat exposure deserves attention because the testicles need to stay a few degrees cooler than core body temperature for normal sperm production. Frequent hot tub or sauna use, prolonged laptop use on your lap, and jobs requiring long hours of sitting in hot environments can all suppress sperm counts temporarily. Tight underwear gets a lot of attention, but the evidence is weaker. Sustained, significant heat sources matter more.
Heavy alcohol use, anabolic steroid use (which can shut down sperm production entirely), and certain medications including some antidepressants and testosterone replacement therapy are also well-documented causes of reduced fertility. If you’re taking testosterone supplements for low T, this is particularly important to know: external testosterone signals your body to stop producing its own, and sperm production drops dramatically as a result.
What the Diagnostic Process Looks Like
The initial evaluation is simpler than many men expect. It starts with a medical history covering past surgeries, medications, sexual function, and how long you’ve been trying to conceive. A physical exam checks testicle size, looks for varicoceles, and assesses signs of hormonal problems. Then comes the semen analysis.
Imaging like scrotal ultrasound or pelvic MRI isn’t part of the routine first visit. The American Urological Association recommends against ordering these upfront. They become relevant only when initial results point to something specific, such as a suspected blockage in the ejaculatory ducts suggested by very low volume, acidic semen with no sperm.
The process is designed to move from broad screening to targeted investigation. A normal semen analysis with a year of unexplained infertility means attention likely shifts to evaluating the female partner. An abnormal analysis leads to hormone testing, possibly genetic testing, and a conversation about treatment options ranging from lifestyle changes to surgical repair to assisted reproduction techniques.