Men Have a Biological Clock Too - It's just not talked about enough

If you've ever heard the phrase "biological clock," chances are you pictured a woman, as this statement usually refers a women or person with ovaries running out of time to have a baby. And that makes sense, because the conversation around age and fertility has, for decades, been almost entirely focused on the female side of the equation. Until now...

But here's the thing: male fertility changes with age too, and it's just not talked about nearly enough. This is a conversation that's long overdue...

The myth: Men are fertile their whole lives

Yes, men and people with testes can produce sperm their whole lives. Unlike women or people with ovaries, who are born with all the eggs they'll ever have, new sperm is produced roughly every 74 days.

So technically, the ability to reproduce and conceive can continue well into older age. But here's the important distinction: It doesn't mean sperm quality stays the same or that they can easily conceive over their whole life. And that's where paternal age starts to matter!

How sperm health changes after 40

After the age of 40, a few things start to shift in sperm health:

• Sperm motility (the ability of sperm to move and swim effectively) begins to decline.

• Morphology (which refers to the shape of sperm) can also be affected.

• Sperm DNA fragmentation, which is essentially damage to the genetic material carried in sperm, increases with age.

• Testosterone levels can decrease, which in turn can impact both erections and sperm production.

• There's also an increase in time to conception.

  
  

To be clear, none of this means men over 40 can't conceive...But it simply means that age affects both partners, and both partners' fertility is worth paying attention to.

What the research actually says

The research on paternal age paints a pretty clear picture.

• Men over 45 are associated with a longer time to conception, even when their female partner is under 25. This directly challenges the idea that male age is irrelevant when a younger woman is involved.

• Men over 50 are associated with an increased risk of pregnancy complications, such as low birth weight and preterm birth, and they are twice as likely to need IVF compared to younger men.

• Research also links older paternal age to a higher risk of certain genetic conditions in children, such as autism, schizophrenia and bipolar disorder, due to the increased DNA fragmentation that comes with age.

  
  

Here's the good news: sperm is responsive to lifestyle changes

This is the genuinely hopeful part of the story. Because men and people with testes produce new sperm every 74 days, they are in a unique position where they can greatly impact their sperm health. As sperm are far more responsive to lifestyle changes than egg health (because women and people with ovaries can't make new eggs).

So what a man does right now, the food he eats, how much he sleeps, whether he smokes, how much alcohol he drinks, can genuinely improve sperm quality in as little as three months. That's a meaningful window of opportunity that doesn't exist in the same way for female fertility.

Things that support sperm health at any age

The evidence points to a handful of genuinely useful lifestyle factors.

• A balanced diet rich in antioxidants helps protect sperm from oxidative damage.

• Regular exercise supports healthy testosterone levels and overall reproductive health.

• Prioritising sleep matters more than most people realise for hormone regulation.

• Quitting smoking and vaping makes a real difference to sperm count and motility.

• Reducing alcohol consumption is worthwhile, as even moderate drinking has been linked to lower sperm quality.

• Investigating and managing any medical conditions such as high blood pressure and diabetes can see improvements in sperm health.

• Managing chronic stress helps keep the hormones involved in sperm production functioning well.

• Avoiding excessive heat to the testes, so fewer long saunas, hot baths and laptops on laps, supports the temperature-sensitive process of sperm production.

• And reducing exposure to endocrine disrupting chemicals (EDCs), which are found in some plastics, pesticides and personal care products, is a practical step worth taking.

  
  

Fertility is not just a female issue

The bottom line is this: fertility is not just a female issue, and age is not just a female issue. The conversation needs to include both partners, because TTC is a team effort.

If you're trying to conceive and the focus has been entirely on the female side of the equation, it might be time to widen the lens. A baseline semen analysis is one of the simplest, most useful pieces of information a couple can have early in their TTC journey, and it's something I encourage regularly in consultations, if it hasn't already been completed.

But then even if they get told "your swimmers are amazing," men can still make changes to their lifestyle to make their sperm EVEN better. This is because a "normal" result sometimes only represents the low end of the spectrum of normal, typically the 5th centile. So don't settle for 'everything is normal, nothing needs to be done', there are so many things within their control that can help sperm health or be investigated if needing more answers.

Want to know what more you can do help your sperm health? Book a FREE nurse chat here and we can talk all about male fertility and investigations or download my Fertility Lifestyle Factors for Him ebook here.

References

Mohamed A.M Hassan, Stephen R Killick, Effect of male age on fertility: evidence for the decline in male fertility with increasing age, Fertility and Sterility, Volume 79, Supplement 3, 2003, Pages 1520-1527, ISSN 0015-0282, https://doi.org/10.1016/S0015-0282(03)00366-2.

Ha AS, Scott M, Zhang CA, Li S, Langroudi AP, Glover F, Basran S, Del Giudice F, Shaw GM, Eisenberg ML. Sociodemographic Trends and Perinatal Outcomes in Fathers 50 Years and Older. JAMA Netw Open. 2024 Aug 1;7(8):e2425269. doi: 10.1001/jamanetworkopen.2024.25269

Kaltsas A, Moustakli E, Zikopoulos A, Georgiou I, Dimitriadis F, Symeonidis EN, Markou E, Michaelidis TM, Tien DMB, Giannakis I, Ioannidou EM, Papatsoris A, Tsounapi P, Takenaka A, Sofikitis N, Zachariou A. Impact of Advanced Paternal Age on Fertility and Risks of Genetic Disorders in Offspring. Genes (Basel). 2023 Feb 14;14(2):486. doi: 10.3390/genes14020486

Bocu K, Boeri L, Mahmutoglu AM, Vogiatzi P. Can lifestyle changes significantly improve male fertility: A narrative review? Arab J Urol. 2024 Nov 1;23(3):190-200. doi: 10.1080/20905998.2024.2421626