It’s widely known that female fertility declines with age, but what about men? Do men have a biological clock too? While men don’t experience the same sharp decline in fertility as women, age does play a significant role in sperm health and reproductive potential. Here’s what science says about when men are most fertile and how aging impacts male fertility.

When Are Men Most Fertile?

Unlike women, who are born with a finite number of eggs, men produce sperm continuously throughout their lives. The process of creating new sperm—called spermatogenesis—typically takes 64 to 74 days.

However, while sperm production doesn’t stop with age, the quality of that sperm can change. Research shows that key sperm parameters—such as motility (movement) and morphology (shape)—tend to decline over time. In simple terms, sperm from a 40-year-old may not be as viable as sperm from a 30-year-old.

Studies vary, but many indicate that sperm quality begins to decrease around age 35. The CDC also notes more substantial declines after age 40. One study found that men over 35 had significantly lower conception rates with intrauterine insemination (IUI) compared to men under 35. Another study showed fertility rates of 52% in men under 35, compared to 25% in men over 35.

So, while there’s no exact age cutoff, most experts agree that male fertility peaks in the early 30s and gradually declines thereafter. That said, many men in their 40s and beyond can still conceive, especially with healthy lifestyle habits and fertility support.

How Age Impacts Sperm Health

A man’s age doesn’t just affect the odds of conception—it can also influence pregnancy outcomes. As men get older, changes in sperm health can lead to longer time-to-conception and may increase the risk of miscarriage. Let’s break down the key aspects of sperm health:

Sperm Count and Concentration

This refers to how many sperm are present in each milliliter of semen. The normal range is between 15 million and 200 million per milliliter. Some studies show that count may decline with age, though fluctuations in diet, lifestyle, stress, and heat exposure can all influence daily sperm count.

Sperm Motility

Motility is the sperm’s ability to swim effectively. It’s crucial because sperm need to reach and fertilize the egg. Motility tends to decrease with age—dropping about 0.8% per year. In one study, men over 55 showed a 54% reduction in motility compared to younger men aged 30–35.

Sperm Morphology

Morphology describes the shape and structure of sperm. Healthy sperm have an oval head, midpiece, and tail. Aging is associated with a higher proportion of abnormally shaped sperm, which can reduce the chances of successful fertilization.

Sperm DNA Fragmentation (SDF)

This refers to breaks or damage in the sperm’s genetic material. Higher levels of fragmentation have been linked to reduced fertility and increased miscarriage risk. SDF tends to increase with age and can also be worsened by oxidative stress, inflammation, smoking, poor diet, and alcohol consumption.

How to Support Male Fertility as You Age

The good news? Lifestyle choices can significantly support sperm quality, even as you age. Some of the most effective changes include:

• Maintaining a healthy weight

• Exercising regularly to boost antioxidants and metabolic health

• Eating a balanced diet, rich in fruits, vegetables, and omega-3 fatty acids (like those found in salmon or sardines)

• Avoiding smoking and excess alcohol

• Limiting exposure to high heat (like saunas, hot tubs, or laptops on laps)

• Reducing intake of artificial sweeteners such as aspartame

• Considering targeted supplements that support sperm health, including CoQ10, zinc, folate, and antioxidants

Research has shown that men who eat more fish have up to 65% higher sperm concentrations, thanks in part to the omega-3 content that supports sperm membrane structure and mobility.

Do Men Ever Stop Producing Sperm?

Typically, no. Most healthy men continue to produce sperm well into older age. However, while production may continue, sperm quality tends to decrease over time, which can affect fertility and the health of potential offspring.

The Bottom Line

While men don’t face the same fertility time crunch as women, age still plays a significant role in reproductive health. Fertility tends to decline gradually after the mid-30s, with noticeable changes in sperm quality and pregnancy outcomes. The good news? Positive lifestyle habits and proper nutritional support can help preserve and even enhance male fertility at any age.

Disclaimer

The information provided in this blog is for educational purposes only and is not intended as a substitute for professional medical advice. Always consult a qualified healthcare provider before making any changes to your health regimen, especially if you are pregnant, nursing, or taking any medications.