Average Sperm Count by Age: What Men Should Know for Fertility Health

Written By The Mr. Fertyl Research & Education Team

Talking about sperm count and fertility can feel a bit awkward, but it’s an important conversation – and nothing to be embarrassed about. Men’s fertility is a normal part of health, just like any other aspect of wellbeing. In fact, understanding how sperm count changes with age can empower you to make informed choices for your reproductive health. Men, unlike women, produce new sperm throughout life, but age still impacts sperm quantity and quality [2][6]. In this post, we’ll explore average sperm counts by age, why sperm count matters for fertility, and what you can do to keep your sperm (and yourself) healthy over the years. Along the way, we’ll also discuss factors like lifestyle and even underwear choices – yes, your boxers vs. briefs debate has a role here – in maintaining fertility. (Spoiler: we’ll see how something as simple as eco-friendly underwear might help!)

Why Sperm Count Matters for Fertility

Sperm count refers to the number of sperm present in a milliliter of semen. It’s one of the key parameters in male fertility, alongside sperm motility (movement) and morphology (shape). When trying to conceive, having more healthy sperm generally increases the chances that one will reach and fertilize the egg. Even though it only takes one sperm to fertilize an egg, a higher sperm count improves the odds of pregnancy each month [2][7].

Medical experts define a “normal” or healthy sperm concentration as at least about 15 million sperm per milliliter (mL) of semen, up to over 200 million per mL [7]. Counts below 15 million/mL (or fewer than 39 million total per ejaculate) are considered low – a condition called oligospermia [7]. Low sperm count can make it harder to conceive naturally. It may also sometimes signal underlying health issues (for example, research has linked low sperm count with higher body fat and blood pressure, indicating it can be a broader health indicator) [7]. On the flip side, very high counts (200 million+ per mL) are above average but don’t necessarily confer much extra fertility benefit beyond a certain point. In general, as long as you’re in the normal range and your swimmers are motile and well-shaped, you have a good shot at making a baby.

It’s important to remember that sperm quality matters in addition to quantity [2]. So, while this article focuses on count, keep in mind that slower-moving sperm or abnormal sperm can also reduce fertility even if count is high. Now, let’s dive into how age comes into play.

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Average Sperm Count by Age

Men don’t have a sudden “fertility cliff” like women do with menopause, but there are gradual changes in sperm count and quality as the years pass. Here’s a decade-by-decade look at the typical sperm counts and what’s happening:

  • Twenties: This is often the peak period for male fertility. Young men in their 20s tend to have the highest average sperm counts. One source estimates an average sperm concentration around 55–75 million per mL for men aged 20–29 [8]. In practical terms, that means most healthy young men have sperm counts comfortably in the “normal” range (15+ million/mL), and often well above that. Sperm are also generally highly motile and healthy in morphology at this age. This makes sense – biologically, the late teens through late 20s are the prime reproductive years for most men [6].

  • Thirties: In the 30s, sperm count typically only slightly declines for many men. Don’t worry – most men in their 30s remain very fertile. Average sperm concentration might be on the order of 50–70 million per mL in the early 30s, gradually trending toward the lower end of that range by the late 30s [8]. In fact, many men won’t notice any difference from their 20s. However, subtle changes do begin: research shows sperm quality begins to decline around age 30 [6]. By the late 30s, more of a decline may be evident. For example, damage to sperm DNA tends to increase by about age 36–37 [6]. So while count may still be well within normal, the percentage of perfectly normal, fast-swimming sperm might dip a bit. It’s a gentle, gradual change – not a cliff.

  • Forties: Once into the 40s, the natural decline in sperm count and fertility potential becomes more noticeable. A man in his 40s still produces millions of sperm daily, but the average sperm count in the mid-40s can be roughly 40–60 million per mL, tapering further by the late 40s [8]. Studies confirm that men over 40 have fewer healthy sperm on average than younger men [9][10]. One classic finding: in test tissue, about 90% of seminiferous tubules (the structures that generate sperm) contained developing sperm cells in men aged 20–30, whereas only ~50% did so in men in their 40s and 50s [9]. This doesn’t mean older men can’t father children (many do), but it illustrates the biological slowdown. In real-world terms, fertility specialists observe that it often takes longer for couples to conceive when the dad is over 40. In fact, one large study found that after controlling for the mother’s age, the chance of conceiving within a year was about 30% lower for men over 40 compared to men under 30 [9]. Total sperm count, semen volume, and motility all trend downward in this decade [11]. Many men remain fertile, but it may require a bit more patience or assistance.

  • Fifties and Beyond: There is no male “menopause” – men can produce sperm well into their 50s, 60s, and beyond – but fertility does continue to decline. By the 50s, average sperm concentrations may fall to roughly 40 million per mL or below [8]. It’s not uncommon for men over 50 to have counts on the lower end of normal, or even below normal, though every individual varies. Sperm motility (how well they swim) is often reduced, and a higher proportion of sperm may have DNA fragmentation or abnormal shape by this age [3][6]. In practical terms, older men may find conceiving naturally can take significantly longer. There are also slightly higher risks of certain genetic issues in children of older fathers (due to those accumulated DNA mutations in sperm) – though the vast majority of older dads still have perfectly healthy kids. Many men in their 50s and 60s do successfully father children (sometimes with a little help from fertility medicine). But from a statistical standpoint, the odds of infertility or sub-fertility are higher in this group. For instance, one study noted men above 50 were over 6 times more likely to have a low sperm count (classified by World Health Organization criteria) compared to men in their twenties [3].

The bottom line: On average, sperm count peaks in the late 20s and then gradually decreases with age – with more marked declines sometime after 40 [6]. However, these are averages and ranges, not destiny for every individual. Plenty of men in their 40s or 50s have decent sperm counts, and some younger men can have fertility issues. Age is just one factor. Now, let’s discuss why sperm count changes and what other factors can speed up or slow down those changes.

Why Sperm Count Changes With Age (and Factors That Influence It)

It’s normal for sperm count and overall semen quality to slowly decline as part of the aging process. There are a few reasons behind this natural trend:

  • Hormonal changes: Testosterone, the male sex hormone, plays a big role in sperm production. Men’s testosterone levels gradually decrease with age. By the 40s and 50s, testosterone is noticeably lower than in the 20s. This can translate to lower sperm output since testosterone is a key signal for the testicles to produce sperm [6].

  • Testicular and cellular changes: Over time, the testicular tissue ages. The seminiferous tubules may not be as efficient at sperm production. As noted earlier, fewer areas in the testes actively produce sperm in an older man versus a young man [9]. The testes may also become slightly smaller or softer with age [11]. Additionally, cellular stress over years can lead to more DNA damage in sperm. Oxidative stress accumulates due to years of exposure to toxins, illness, or just normal metabolism, which can harm the sperm-producing cells. By the late 30s and 40s, sperm are more likely to carry DNA fragments or mutations [3][6].

  • General health and diseases: As men get older, they’re more likely to develop other health issues (high blood pressure, diabetes, etc.) that can indirectly impair fertility. For example, conditions like diabetes or obesity can lower testosterone and harm sperm parameters. An enlarged prostate (benign prostatic hyperplasia) is common with aging and might affect ejaculatory function [11]. Chronic illnesses or the medications to treat them (for instance, certain blood pressure meds, opioids, or antidepressants) can also negatively affect sperm production or sexual function [2]. In short, a 50-year-old body isn’t the same as a 25-year-old body, and that can reflect in reproductive function.

  • Lifestyle and exposures: Some factors can accelerate the decline in sperm count – and the good news is many of these are modifiable. Here are a few big ones. Smoking: Smoking tobacco is strongly linked with reduced sperm count and poor sperm motility [2]. The toxins in cigarettes cause oxidative stress and DNA damage to sperm. Long-term smokers often see a faster drop in fertility with age than non-smokers. (Yet another reason to quit smoking – your future kids will thank you!). Alcohol and drug use: Heavy alcohol use can lower testosterone and sperm production, leading to lower counts [2]. Certain drugs (anabolic steroids, for example) can severely suppress sperm production. Even some prescriptions can have side effects that impact fertility – always review with your doctor if you’re trying to conceive [2]. Weight and diet: Being overweight or obese can decrease sperm count. Research suggests that as body mass index (BMI) rises, sperm count and motility tend to fall [2]. Excess fat can alter hormone levels (increasing estrogen, lowering testosterone) which hurts sperm output. Poor diet lacking in essential nutrients may also contribute to oxidative stress. On the flip side, a healthy diet rich in antioxidants (like vitamin C, vitamin E, zinc, selenium, CoQ10, etc.) may slow age-related sperm decline by protecting sperm from damage. Stress: Chronic stress isn’t good for sexual health or fertility. High stress can throw off the hormone signals between your brain and testicles, potentially lowering testosterone and sperm production. Stress can also reduce libido and sexual function [2], indirectly affecting chances of conception. Managing stress through exercise, meditation, or therapy can improve overall reproductive health. Environmental toxins: Unfortunately, our modern environment exposes us to various chemicals that can harm reproductive health. Long-term exposure to pesticides, heavy metals, and endocrine-disrupting chemicals (found in some plastics and personal care products) has been implicated in declining sperm counts [2][4]. There’s ongoing research into how things like phthalates or BPA might reduce sperm count or quality. While we can’t avoid every toxin, being mindful (e.g., using natural products when possible, avoiding unnecessary chemical exposures) can only help. Interestingly, scientists have noted that sperm counts worldwide have dropped significantly over the past few decades, and one suspected cause is increased environmental pollution and toxic exposures [4]. It’s a stark reminder that what’s bad for the planet can be bad for our fertility, too. Heat and underwear choice: You’ve probably heard the boxers vs. briefs debate. The issue comes down to heat. Sperm production thrives when the testes are a few degrees cooler than core body temperature – that’s why they hang outside the body. If anything raises scrotal temperature too much (like hot tubs, saunas, or tight underwear that holds the testes close to the body), it can temporarily lower sperm count [2]. In fact, frequent exposure to high heat can have a lasting impact on sperm production. So, does underwear really matter? Research suggests it can. A large Harvard study found that men who usually wore loose-fitting boxer shorts had significantly higher sperm concentrations and total counts (25% higher concentration and 17% higher count on average) than men who wore tight briefs [5]. Essentially, tighter undies slightly increase testicular heat, which can impair sperm output. The good news is this effect isn’t permanent – switching to cooler, breathable underwear can improve matters over time (sperm take ~3 months to develop, so improvements show up after a few months of change) [5]. Apart from underwear, even habits like long hours of sitting (hello, desk jobs) or placing a laptop directly on your lap can warm things up down there. It’s recommended to take breaks, stand up and move around, and avoid prolonged heat exposure to the groin area when you’re aiming for optimal fertility.

Given all these factors, it’s clear that age itself is only one part of the fertility puzzle. Two men of the same age can have very different sperm counts depending on their genetics and lifestyle. You can’t change your age, but you can address many of the above factors. Next, let’s look at some actionable steps to maintain a healthy sperm count and support fertility – at any age.

Tips for Maintaining Healthy Sperm Levels as You Age

While we can’t stop time (sadly, no one’s figured that out yet!), there are plenty of ways to keep your sperm as healthy as possible through the years. Men in their 30s, 40s, 50s and beyond who want to preserve fertility should consider the following tips:

  • Maintain a healthy lifestyle: This encompasses a balanced diet, regular exercise, weight management, and stress reduction. Fuel your body with fertility-friendly nutrients: foods high in antioxidants (fruits, vegetables, nuts) help combat oxidative damage to sperm. Omega-3 fatty acids (found in fish, flaxseed) may improve sperm motility. Staying active keeps testosterone levels healthier and improves blood flow – including to reproductive organs. Just avoid extreme exercise or overheating. Manage stress through meditation, yoga, or therapy if needed; reducing stress can normalize hormonal balance.

  • Quit smoking and limit alcohol: If you smoke, seek help to quit – your sperm count will thank you. Studies show smokers have lower sperm counts and more DNA damage in sperm [2]. Alcohol in moderation is generally fine, but heavy drinking can depress sperm production and sexual function [2]. Stick to recommended limits (no more than 1-2 drinks per day) or less when trying to conceive. And needless to say, avoid illicit drugs or anabolic steroids – these are sperm killers (steroids can actually shut down natural sperm production entirely).

  • Stay cool (literally): Protect your “boys” from excessive heat. This means avoiding long stints in hot tubs or saunas, especially in the few months before trying for a baby. Even frequent very hot baths could impact your sperm for a while. Choose loose-fitting pants and underwear that allow some breathability. Here’s where Mr. Fertyl’s bamboo underwear comes into play. Our bamboo fabric boxers are designed to be ultra-breathable and moisture-wicking, keeping you cool and comfortable. Bamboo as a material is not just eco-friendly; it also helps regulate temperature better than many synthetic fabrics. By wearing cooler, breathable underwear, you can avoid “cooking” your sperm and potentially boost your sperm count and motility – all while being kind to the environment with sustainable fabric. It’s a simple switch that can make a real difference over time. Plus, they’re pretty darn comfortable for everyday wear (who says improving fertility can’t feel good?).

  • Watch out for toxins: Try to minimize exposure to pesticides, industrial chemicals, and other environmental toxins whenever possible. Use protective gear if you work with chemicals. At home, consider using more natural cleaning products and personal care items free of phthalates and parabens. Filter your drinking water if you suspect contaminants. These steps can help reduce the chemical burden on your body. It’s impossible to avoid everything, but every little bit helps. Supporting environmental causes and choosing eco-friendly products (like Mr. Fertyl’s sustainable bamboo clothing) isn’t just great for the planet – it creates a healthier environment for your fertility too.

  • Get regular health checkups: Keep tabs on blood pressure, blood sugar, and overall health. Conditions like hypertension or diabetes can sneak up with age and can impair fertility if uncontrolled. By staying on top of your health conditions and treating them, you minimize their impact on sperm production. Also, discuss any medications with your doctor to see if they could affect fertility. In some cases, alternative meds or dosages might be an option when you’re actively trying to conceive [2].

  • Consider supplements wisely: Many over-the-counter male fertility supplements contain vitamins like C, E, and minerals like zinc or selenium, thought to support sperm health. There’s some evidence these antioxidants can improve sperm parameters, especially in older men or those with diagnosed issues. They’re not a cure-all, but if your diet is lacking, a quality supplement could help fill gaps. Always talk to a healthcare provider before starting supplements, especially if you have medical conditions.

  • Sperm testing and banking: If you’re in your 40s or beyond and know you want children (or more children) in the future, it might be worth getting a semen analysis sooner rather than later. This can give you a baseline of your sperm count, motility, and morphology. If results are not ideal, you can take early action with lifestyle changes or fertility treatments. In some cases, men choose to freeze sperm (sperm banking) at a younger age as a proactive step, especially if they plan to have kids much later or if they’re facing something that could affect fertility (like cancer treatment or a high-risk job). Sperm freezing is a reliable way to essentially “pause” your sperm in time – frozen sperm can be used later for IVF or insemination. According to the Cleveland Clinic, men over 40 may want to consider banking sperm as sperm quality typically starts decreasing past that age [1]. It’s a personal choice, but modern reproductive technology offers many options to extend one’s fertility timeline.

  • Stay informed and open: Don’t shy away from discussing fertility with your partner or doctor. There’s still a bit of stigma or reluctance among men to talk about these things, but remember that fertility is half of the equation in conceiving – your part is just as important as the woman’s. There’s no shame in getting advice from a urologist or fertility specialist, especially if you’re older or if you’ve been trying to conceive for 6-12 months without success. Sometimes relatively simple interventions can help (for example, medication for hormonal imbalance, or minor surgery for a varicocele that might be affecting testicular temperature). And if more help is needed, specialists can guide you on advanced options like IVF. The earlier you seek help, the better the outcome usually.

By following these tips, you’ll not only support your fertility – you’re likely to improve your overall health, too. Fertility tends to reflect general wellness, so what’s good for your heart, weight, and mind tends to be good for your sperm as well.

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Embracing Fertility Health (and Sustainability)

In summary, sperm count does change as men age: it usually peaks in the 20s and slowly declines in the decades thereafter. By the time a man is in his 40s or 50s, he may have a lower sperm count and lower fertility potential than he did in youth, but this doesn’t mean fatherhood is off the table – far from it. Men can and do father children later in life, especially if they take care of their health. Understanding the typical trends (like the gradual drop in count and motility) can help set realistic expectations and encourage proactive steps.

The great news is that you have some control here. By maintaining a healthy lifestyle – eating right, exercising, not smoking – and by avoiding unnecessary heat or toxins, you can slow down the natural decline and even improve your sperm count at any age [2]. It’s all about preserving the quality of your swimmers. Little everyday choices, like wearing breathable Mr. Fertyl bamboo underwear instead of tight synthetic briefs, add up to create a more fertility-friendly environment for your body. We created Mr. Fertyl products with exactly this in mind: to support men’s reproductive health in a comfortable, convenient way. Our bamboo underwear keeps things cool (boosting your sperm health) and is eco-friendly (boosting planetary health) – a win-win for sustainable fatherhood.

Fertility and environment are two topics that people historically haven’t talked about much in public, but times are changing. It’s completely normal to be curious or concerned about your sperm count as you get older. By bringing these conversations into the open, we hope to make men feel more comfortable discussing and addressing fertility. After all, reproductive health is just health. So whether you’re 25 and planning ahead or 45 and trying for a baby, remember that knowledge is power. Pay attention to your body, make those healthy changes, and don’t hesitate to seek guidance if you need it. With the right approach – and perhaps some high-quality bamboo underwear in your dresser drawer – you can take charge of your fertility journey while also being kind to the environment. Here’s to happy, healthy swimmers and a sustainable future for you and your family!

  1. Cleveland Clinic. (2022, July 15). Sperm Banking. Cleveland Clinic. Source.
  2. Mayo Clinic Staff. (n.d.). Healthy sperm: Improving your fertility. Mayo Clinic. Source.
  3. Pino, V., Sanz, A., Valdés, N., Crosby, J., & Mackenna, A. (2020). The effects of aging on semen parameters and sperm DNA fragmentation. JBRA Assisted Reproduction, 24(1), 82–86. Source.
  4. Leslie, S. W., Soon-Sutton, T. L., & Khan, M. A. B. (2024). Male Infertility. In StatPearls. StatPearls Publishing. Source.
  5. Chacon, A. (2018, August 8). Boxers or briefs? Largest-ever study shows boxers may beat briefs for baby-making. ABC News. Source.
  6. Path Fertility. (2025). Age affects male and female fertility. PathFertility.com. Source.
  7. Chertoff, J. (2025, May 22). What is a typical sperm count? Healthline. Source.
  8. Puranik, S. (2025, January 8). Average sperm count by age – Comprehensive guide. Dr. Supriya Puranik IVF Blog. Source.
  9. Harris, I. D., Fronczak, C., Roth, L., & Meacham, R. B. (2011). Fertility and the aging male. Reviews in Urology, 13(4), e184–e190. Source.
  10. Your Fertility. (n.d.). How age matters for your fertility. Your Fertility. Source.
  11. UT Southwestern Medical Center. (2024, January). How does a father’s age affect fertility and a baby’s health? UT Southwestern Medical Center. Source.