Most men who are sterile or have low fertility don’t have obvious symptoms. The only definitive way to know is through a semen analysis, a lab test that counts your sperm and evaluates how well they move. But there are physical signs, lifestyle patterns, and medical history clues that can tell you whether testing is worth pursuing.
True sterility, meaning a complete and untreatable inability to produce viable sperm, affects roughly 12% of men diagnosed with infertility. The rest fall somewhere on a spectrum of reduced fertility that may respond to treatment. Understanding the difference matters because many men assume the worst when the reality is more nuanced.
Physical Signs That Suggest a Problem
Infertility in men rarely announces itself with dramatic symptoms, which is part of what makes it so easy to miss. Still, a few physical changes are worth paying attention to.
Pain, swelling, or a lump in the testicles can signal an underlying issue. Small or unusually soft testicles may point to reduced sperm production since the testicles are where sperm are made. A decrease in facial or body hair can indicate a hormonal imbalance, specifically low testosterone or disrupted signaling from the pituitary gland. Difficulty maintaining an erection or a noticeable drop in sex drive can also reflect hormonal problems that overlap with fertility issues.
None of these signs on their own confirm sterility. But if you’re noticing one or more of them alongside difficulty conceiving, they’re meaningful clues worth bringing to a doctor.
Ejaculation Problems That Affect Fertility
Sometimes the issue isn’t sperm production but sperm delivery. Retrograde ejaculation is a condition where semen travels backward into the bladder instead of out through the penis during orgasm. The telltale signs are producing very little or no semen when you climax (sometimes called a “dry orgasm”) and noticing that your urine looks cloudy afterward because it contains semen. This condition is more common in men with diabetes, spinal cord injuries, or those who’ve had certain prostate or bladder surgeries.
If you consistently produce very low volumes of ejaculate, that’s a reason to get evaluated. Normal semen volume is at least 1.5 milliliters per ejaculate, roughly a third of a teaspoon.
Conditions That Commonly Cause Infertility
A varicocele is one of the most common treatable causes of male infertility. It’s essentially a cluster of enlarged veins in the scrotum, similar to varicose veins in the legs. You might feel a dull ache in the testicle, notice a visible or palpable mass that feels like a “bag of worms,” or have no symptoms at all. Varicoceles raise the temperature inside the scrotum, which damages sperm over time. Sperm motility (how well they swim) tends to decline first, though concentration and shape can deteriorate gradually as well. A doctor can often detect a varicocele through a physical exam, sometimes confirmed with an ultrasound.
Undescended testicles, even if surgically corrected in childhood, can affect fertility later in life. Prior infections like mumps that involved the testicles, certain medications, and a history of chemotherapy or radiation also carry risk.
Genetic conditions play a role in roughly 15% of all male infertility cases. Klinefelter syndrome, where a man carries an extra X chromosome, is the most frequent genetic cause and affects about one in 660 men. It typically results in very low or absent sperm production. Smaller genetic deletions on the Y chromosome account for another portion, affecting 10 to 15% of men with severely low or absent sperm counts.
What a Semen Analysis Actually Measures
A semen analysis is the cornerstone test. It’s straightforward: you provide a sample through ejaculation, and a lab evaluates it against established benchmarks from the World Health Organization. The key numbers your results will show include:
- Sperm concentration: at least 15 million sperm per milliliter is considered within normal range
- Total sperm count: at least 39 million per ejaculate
- Total motility: at least 42% of sperm should be moving
- Progressive motility: at least 40% should be swimming forward, not just twitching in place
- Morphology: at least 4% of sperm should have a normal shape
- Vitality: at least 54% should be alive
These thresholds represent the 5th percentile among men who have successfully fathered children, so falling below them doesn’t automatically mean you can’t conceive. It means your odds are reduced and further evaluation is warranted.
If the analysis shows zero sperm in the ejaculate, the condition is called azoospermia. About 40% of azoospermia cases are obstructive, meaning sperm are being produced but can’t get out due to a blockage (from a vasectomy, prior surgery, or a birth defect affecting the tubes that carry sperm). The other 60% are non-obstructive, meaning the testicles aren’t producing sperm normally. This distinction matters enormously for treatment options: obstructive cases can often be fixed with surgery, while non-obstructive cases are more complex.
How to Prepare for Semen Analysis
To get accurate results, avoid any sexual activity that causes ejaculation for two to three days before the test, but not longer than five days. Too short a window gives a falsely low count; too long and sperm quality starts to decline.
You’ll collect the sample either at the clinic or at home using a sterile container. If you collect at home, keep the container at body temperature (an inside jacket pocket works) and get it to the lab within 30 minutes. The sample needs to be analyzed within two hours, and sooner is better for reliability. Most doctors will order at least two analyses, spaced a few weeks apart, since sperm counts naturally fluctuate.
At-Home Sperm Tests: What They Can and Can’t Tell You
Several at-home test kits are now available and can give you a preliminary read on your sperm count. The most studied option, SpermCheck Fertility, claims about 98% accuracy for detecting whether your count is above or below a basic threshold. Another kit called SwimCount measures motile sperm concentration with roughly 95% accuracy overall, though its ability to correctly identify men with low counts (sensitivity of 88%) is better than its ability to rule out problems in men with normal counts (specificity of 74%).
The critical limitation is what these tests leave out. None of them evaluate morphology (sperm shape), semen volume, or pH. They give you a single data point, usually just concentration or motility, when a complete picture requires all of them. An at-home test can be a reasonable first step if you want to screen before committing to a clinic visit, but a normal result doesn’t guarantee fertility and an abnormal result doesn’t confirm sterility.
Blood Tests and Genetic Testing
If a semen analysis comes back abnormal, the next step is usually blood work. Doctors measure follicle-stimulating hormone (FSH), which tells the testicles to produce sperm. High FSH levels suggest the brain is working overtime to compensate for testicles that aren’t responding well. Luteinizing hormone (LH), testosterone, and sometimes estrogen levels are checked alongside FSH to get a fuller picture of your hormonal balance.
Genetic testing enters the picture when sperm counts are severely low or absent. The three standard tests are a karyotype analysis (which checks for chromosomal conditions like Klinefelter syndrome), Y-chromosome microdeletion testing (which looks for missing segments of genes essential for sperm production), and CFTR mutation testing (which checks for the gene behind cystic fibrosis, relevant when the tubes that carry sperm are missing from birth). Nearly 7.5% of men with very low or absent sperm counts carry Y-chromosome deletions, and the specific location of the deletion determines whether sperm retrieval for assisted reproduction is even possible. Deletions in certain regions mean no viable sperm will ever be found, which is one of the few scenarios where true, permanent sterility can be confirmed with certainty.
Medical History Red Flags
Your personal history can be just as telling as a lab test. A prior vasectomy is the most obvious cause of zero sperm in the ejaculate, but other surgical histories matter too. Hernia repairs, especially in childhood, can inadvertently damage the vas deferens (the tube that carries sperm from the testicle). Prostate or bladder surgeries increase the risk of retrograde ejaculation.
Exposure to heat is a well-established fertility disruptor. Regular use of saunas, hot tubs, or even prolonged laptop use on your lap can temporarily reduce sperm production. Anabolic steroid use, even in the past, can suppress the hormonal signals that drive sperm production, sometimes for months after stopping. Certain prescription medications, including some for high blood pressure, depression, and inflammatory bowel disease, can also interfere with fertility.
If you’ve been trying to conceive for 12 months without success, or six months if your partner is over 35, that timeline alone is a clinical indication to start testing. You don’t need to have symptoms or a suspicious medical history to justify getting a semen analysis. For many men, the test itself is the only way to know.