For years, conversations about the “biological clock” have centered on women but science now shows that men have one too. While men don’t experience menopause or a sharp fertility cutoff, age still affects sperm health, conception chances, and even a child’s long-term well-being.
More men today are choosing to become fathers later in life, whether by choice, circumstance, or second marriages but what really happens when you have kids after 40?
Fertility Doesn’t Stay the Same Forever
According to a report by UT Southwestern Medical Center, sperm count and movement decline after 40, making conception take longer. One study found that men above 40 have about a 30% lower chance of conception compared to men in their 20s.
That doesn’t mean it’s impossible but couples might need more time or medical help to conceive.
Pregnancy and Baby Health Risks
The Stanford University School of Medicine found that children born to fathers over 45 faced a 14% higher chance of premature birth, and that risk nearly doubled for men over 50.
Research published on PubMed Central (PMC) also links advanced paternal age to a small increase in genetic mutations, which can contribute to conditions like autism, schizophrenia, and developmental delays.
While the risks are modest, they highlight that a man’s age plays a role not just the woman’s.
What This Doesn’t Mean
Being over 40 doesn’t disqualify you from fatherhood or doom you to complications. Experts emphasize that most older fathers go on to have healthy children. But understanding the risks helps families plan better.
As one review on PMC put it:
“The current body of knowledge does not justify dissuading older men from trying to initiate a pregnancy, only that they should be aware of potential risks.”
How to Boost Fertility After 40
See a doctor early. A fertility or urology check-up can reveal sperm quality and guide next steps.
Watch your lifestyle. Smoking, alcohol, poor diet, and obesity can worsen sperm health.
Manage your health. Chronic illnesses like diabetes or hypertension can affect fertility.
Talk with your partner. Combine both partners’ health and timelines when planning.
The Bottom Line
Age isn’t everything, but it does matter.
The male biological clock may tick more quietly than the female one, but it ticks nonetheless. So if you’re planning to start a family after 40, take charge of your health, seek medical advice, and prepare for a journey that’s both fulfilling and informed.
