Most men with fertility problems have no obvious symptoms. The clearest sign is the simplest one: you and your partner have been having regular, unprotected sex for a year without achieving pregnancy. At that point, both partners should be evaluated. If the female partner is over 35, that timeline shortens to six months.
Beyond that benchmark, there are physical signs, lifestyle factors, and medical tests that can reveal whether a man’s fertility is compromised, sometimes long before a couple starts trying.
Physical Signs You Might Notice
Male infertility rarely announces itself with dramatic symptoms, but a few physical changes can point to an underlying problem. One of the most common is a varicocele, an enlarged vein in the scrotum that feels like a soft lump above the testicle. Larger varicoceles have a distinctive texture sometimes compared to a bag of worms. They can cause a dull ache that improves when you lie down, and they contribute to roughly 40% of all male infertility cases. The extra blood pooling raises the temperature inside the scrotum, which can impair sperm production in both testicles.
Other signs worth paying attention to:
- Testicle changes. Shrinking, softening, or noticeable swelling in one or both testicles can signal a hormonal or structural problem.
- Low sex drive or difficulty with erections. These may reflect low testosterone, which also affects sperm production.
- Pain or swelling in the groin area. This could indicate infection, injury, or a varicocele.
- Reduced body or facial hair, breast tissue growth, or loss of muscle mass. These are signs of hormonal imbalance, particularly low testosterone.
- Problems with ejaculation. Very low semen volume, retrograde ejaculation (where semen enters the bladder instead of exiting), or difficulty ejaculating at all can each prevent sperm from reaching an egg.
None of these signs guarantee infertility, and many infertile men have none of them. But if you notice any of these changes, they’re worth bringing up with a doctor whether or not you’re currently trying to conceive.
Medical History That Raises Risk
Certain events in your past significantly increase the chance of fertility problems. Undescended testicles at birth are one of the strongest risk factors. If one or both testicles didn’t move into the scrotum on their own during infancy, sperm production can be permanently affected even if the condition was surgically corrected.
Other history red flags include groin or testicular surgery, chemotherapy or radiation treatment, serious infections (especially mumps after puberty), and repeated exposure to high heat in the scrotal area from occupational hazards or prolonged sauna use. A family history matters too. Having a father or brother with fertility problems or reproductive issues can point toward a genetic component. If any of these apply to you, it’s reasonable to get tested before spending a year trying to conceive.
How Body Weight and Smoking Affect Sperm
Carrying extra weight has a measurable effect on sperm. A large analysis from Harvard found that overweight men were 11% more likely to have a low sperm count and 39% more likely to have no sperm at all in their ejaculate. For obese men, the numbers were starker: 42% more likely to have a low count and 81% more likely to produce no sperm compared to men at a normal weight.
Smoking damages sperm in multiple ways, reducing count, slowing motility (how well sperm swim), and increasing the percentage of abnormally shaped sperm. Heavy alcohol use and anabolic steroid use can suppress the hormones that drive sperm production, sometimes shutting it down entirely. These are among the most actionable risk factors because they’re reversible. Sperm production takes about 72 days per cycle, so improvements in weight, smoking status, or substance use can show results in roughly three months.
What a Semen Analysis Reveals
The single most informative fertility test for men is a semen analysis. It’s the first test a doctor will order, and it evaluates three key parameters: concentration (how many sperm per milliliter), motility (what percentage are swimming effectively), and morphology (what percentage have a normal shape). All three matter. A man can have a high sperm count but poor motility, or normal motility but too few sperm to give conception a realistic chance.
A complete absence of sperm in the ejaculate, called azoospermia, affects a meaningful number of infertile men and requires further investigation to determine whether the cause is a production problem or a blockage. Severely low counts, generally below 20 million sperm per milliliter, also warrant additional testing.
Because sperm quality can fluctuate from week to week based on illness, stress, or heat exposure, doctors typically repeat the analysis at least once if results are abnormal. One bad result doesn’t necessarily mean permanent infertility.
Home Sperm Tests: What They Can and Cannot Tell You
Several FDA-cleared home sperm tests are now available, and they can be a reasonable first step if you want preliminary information before visiting a clinic. Most home kits measure only sperm concentration, which tells you whether your count is above or below a threshold but nothing about motility or morphology. Newer devices like the YO Home Sperm Test measure motile sperm concentration, combining count and movement into a single number, and showed 97.8% accuracy when compared against laboratory equipment in clinical testing.
The limitation is real, though. A home test might tell you your motile sperm concentration looks normal while missing that a high percentage of your sperm are abnormally shaped. It’s a useful screening tool, not a diagnosis. If a home test comes back low, or if you’ve been trying for a year with normal home results, a full lab analysis is the next step.
Hormone and Blood Tests
When a semen analysis shows very low or absent sperm, blood tests help identify why. The core hormone panel includes FSH (which signals the testicles to produce sperm), LH (which triggers testosterone production), total and free testosterone, and prolactin. The pattern of these results tells a doctor whether the problem originates in the brain’s signaling system or in the testicles themselves.
High FSH with low sperm counts typically means the brain is sending the right signals but the testicles aren’t responding, pointing to a production problem. Low FSH and low testosterone suggest the brain isn’t sending adequate signals in the first place, which is often treatable with hormone therapy. Elevated prolactin can indicate a small pituitary gland issue that’s suppressing the entire system.
Genetic Causes of Male Infertility
Genetics play a larger role in male infertility than many people realize. The most common genetic cause is Klinefelter syndrome, where a man carries an extra X chromosome. This typically results in very low or absent sperm production, smaller testicles, and sometimes reduced testosterone levels.
Another major category involves tiny deletions on the Y chromosome, specifically in a region that contains genes essential for sperm development. These microdeletions show up in 10% to 15% of men with no sperm in their ejaculate and 5% to 10% of men with severely low counts. The specific location of the deletion matters: some deletions eliminate sperm production entirely, while others leave enough function that sperm can sometimes be retrieved directly from the testicle for use in assisted reproduction.
Genetic testing is typically recommended when sperm counts are extremely low or zero, or when there’s a family history of reproductive problems. The results don’t just explain the current situation. They also help predict whether treatments like sperm retrieval procedures are likely to succeed.
Imaging and Physical Exams
A physical exam of the genitals is a standard part of any male fertility evaluation. The doctor checks testicle size (smaller testicles often produce less sperm), feels for varicoceles, and looks for any structural abnormalities. Varicoceles are graded on a scale: the smallest are detectable only by ultrasound, while larger ones are easy to feel during a physical exam.
A scrotal ultrasound provides a detailed look at the testicles and surrounding structures, confirming varicoceles too small to feel and identifying other issues like cysts or blockages. In cases where a blockage in the reproductive tract is suspected, particularly when semen volume is very low, additional imaging can locate where the obstruction is and help determine whether surgical correction is feasible.
What the Results Mean for Next Steps
Male infertility has a wide range of causes, and many are treatable. Varicoceles can be repaired surgically, often improving sperm quality within a few months. Hormonal imbalances can sometimes be corrected with medication. Blockages can be surgically opened. Lifestyle-related declines in sperm quality frequently reverse with weight loss, smoking cessation, or stopping testosterone supplements or anabolic steroids.
When natural conception isn’t possible, sperm retrieved from the ejaculate or directly from the testicle can be used for assisted reproduction. Even men with no sperm in their ejaculate sometimes have sperm being produced in small quantities within the testicle itself. The key takeaway is that a fertility problem identified today doesn’t necessarily mean biological fatherhood is off the table. It means the next step is figuring out exactly what’s going on, and that starts with a semen analysis.