The Risks of Older Fatherhood

Recent decades have seen a significant increase in the average age of fathers across the UK and globally. In 2021, the typical first-time dad in Britain was 33.7 years old, compared to just 29 years old in the 1970s. High-profile older celebrity fathers like Robert De Niro, Mick Jagger, and Billy Joel have drawn attention to later-in-life fatherhood, making it seem increasingly normal and acceptable.

However, growing research suggests there may be important health implications associated with advanced paternal age that couples should understand when planning their families. This guide explores what the science tells us about older fatherhood, the potential risks involved, and what men can do to optimise their fertility as they age.

What Age Is Considered “Older Fatherhood”?

Whilst there’s no universally agreed definition, medical researchers typically consider “advanced paternal age” to begin around 40 years old. Some studies set the threshold at 35, whilst others use 45 as the benchmark. The Human Fertilisation and Embryology Authority (HFEA) notes that male fertility starts to decline gradually after age 40, with more significant changes occurring after 45.

Unlike women, who experience a clear biological endpoint to fertility with menopause, men can theoretically father children well into their senior years. However, this biological capability doesn’t mean fertility remains constant. Sperm quality and quantity both decline with age, and the time it takes to conceive increases significantly for couples where the male partner is over 40.

Health Risks Associated With Advanced Paternal Age

Numerous studies have identified links between advanced paternal age and various health conditions in offspring. Whilst the absolute risks remain relatively small for individual couples, the associations are scientifically established and important to understand.

Neuropsychiatric Conditions

Research has found connections between older fathers and increased rates of autism spectrum disorder, schizophrenia, and bipolar disorder in children. A 2015 systematic review published in the Journal of Psychiatric Research described these connections as “disturbing” and called for greater awareness among healthcare professionals and the public.

Studies suggest that men who father children at age 45 or older have a higher likelihood of having offspring with autism compared to fathers in their twenties and early thirties. The mechanisms behind this association aren’t fully understood, but likely involve accumulated mutations in sperm DNA over time.

Childhood Cancers and Other Conditions

Advanced paternal age has also been linked to slightly elevated risks of childhood leukaemia and other rare cancers. Additionally, some research suggests associations with birth defects, though the evidence here is less consistent than for neuropsychiatric conditions.

It’s important to emphasise that these risks, whilst statistically significant in large population studies, remain quite low in absolute terms. Most children born to older fathers are perfectly healthy. However, understanding these potential risks allows couples to make informed decisions about family planning.

Why Male Fertility Declines With Age

Several biological changes occur in men as they age that affect their reproductive capacity:

DNA Fragmentation and Genetic Quality

DNA fragmentation increases significantly in ageing men’s sperm, meaning the genetic material becomes damaged or broken. This fragmentation is one of the primary contributors to fertility problems in older men. According to the NHS, sperm DNA damage can affect both the ability to conceive and the health of any resulting pregnancy.

Unlike eggs, which are all present at birth in women, sperm are continuously produced throughout a man’s life. However, the cellular machinery responsible for sperm production becomes less accurate over time, leading to an accumulation of genetic mutations. Some estimates suggest that men acquire about two new mutations per year in their sperm-producing cells.

Reduced Sperm Parameters

Studies show that sperm concentration, motility (movement), and morphology (shape) all decline with age. Men over 45 typically have lower sperm counts and a higher percentage of abnormally shaped sperm compared to younger men. This makes conception more difficult and can reduce the chances of success with assisted reproductive technologies like IVF.

Hormonal Changes

Testosterone levels gradually decrease with age, typically by about 1% per year after age 30. Lower testosterone can affect sperm production and sexual function, both of which impact fertility. However, the effect of declining testosterone on male fertility is less dramatic than the hormonal changes women experience during menopause.

How Paternal Age Affects Pregnancy Outcomes

Advanced paternal age doesn’t just affect the time it takes to conceive or the health of children—it also influences pregnancy outcomes themselves.

Research from the Royal College of Obstetricians and Gynaecologists (RCOG) indicates that couples with older male partners have higher rates of miscarriage, even when controlling for maternal age. They also have increased risks of preterm birth and pregnancy complications.

In IVF treatments, success rates decline when the male partner is older, particularly after age 45. This occurs even when using young donor eggs, demonstrating that paternal age has an independent effect on pregnancy outcomes beyond just maternal factors.

Can Younger Partners Offset These Risks?

Some research suggests that younger women’s eggs may repair certain DNA defects in sperm from older men after fertilisation. A younger partner’s cellular machinery could potentially fix some genetic problems, reducing—but not eliminating—risks associated with advanced paternal age.

However, this repair mechanism has limitations. Paternal age contributes independently to various disorders, and the complex interactions between maternal and paternal genetic factors during prenatal development mean that having a younger partner doesn’t provide complete protection.

It’s also worth noting that environmental factors like stress, nutrition, and lifestyle habits in both partners affect conception and pregnancy outcomes. No single factor—including age—determines reproductive success or child health entirely on its own.

Testing Options for Older Men Planning Fatherhood

If you’re an older man planning to start or expand your family, assessing your fertility status is a sensible first step. Home male fertility tests provide a convenient, private way to check key sperm parameters without needing to visit a clinic initially.

Modern home tests can measure sperm concentration and, in some advanced versions, sperm motility as well. These tests help identify potential fertility issues early, allowing you to seek medical advice sooner if needed. Understanding your baseline fertility status is particularly valuable for men over 40 who may be planning conception with partners of various ages.

If home testing reveals low sperm counts or other concerns, your GP can refer you for comprehensive semen analysis at a specialist clinic. These laboratory tests provide detailed information about sperm count, motility, morphology, and DNA fragmentation—giving you and your healthcare provider a complete picture of your fertility status.

Steps to Optimise Male Fertility After 40

Whilst you can’t change your age, there are evidence-based steps you can take to optimise your fertility as you get older:

1. Maintain a Healthy Weight

Obesity negatively affects sperm quality and testosterone levels. Losing excess weight through healthy eating and regular exercise can improve your fertility significantly. Aim for a BMI in the normal range (18.5-24.9).

2. Stop Smoking and Limit Alcohol

Smoking damages sperm DNA and reduces sperm count and motility. Excessive alcohol consumption similarly impairs sperm quality. The NHS recommends stopping smoking completely and limiting alcohol to no more than 14 units per week for men trying to conceive.

3. Manage Stress Effectively

Chronic stress affects hormone levels and can reduce sperm quality. Finding effective stress management techniques—whether through exercise, meditation, or counselling—can support your fertility efforts.

4. Consider Nutritional Supplements

Certain supplements, including zinc, folic acid, selenium, and vitamin C, may improve sperm quality in some men. However, evidence is mixed, and it’s best to consult your GP or a fertility specialist before starting any supplementation regime. Focus first on getting these nutrients through a balanced, varied diet.

5. Avoid Heat Exposure

Testicles need to be slightly cooler than body temperature for optimal sperm production. Avoid hot baths, saunas, and tight underwear that trap heat. If you work in hot environments, take regular breaks in cooler conditions.

6. Review Medications

Some medications can affect sperm production or sexual function. If you’re taking regular medications, speak with your GP about whether they might impact your fertility and whether alternatives are available.

7. Don’t Delay Seeking Help

If you’ve been trying to conceive for six months without success and you’re over 40 (or your partner is over 35), consider seeking medical advice sooner rather than later. Early intervention can make a significant difference to your chances of successful conception.

In Conclusion

The trend towards delayed fatherhood reflects changing social and economic realities. Many men now prioritise education, career development, and financial stability before starting families. Whilst there’s nothing inherently wrong with becoming a father later in life, it’s important to understand the biological realities alongside the practical considerations.

Advanced paternal age does carry some increased risks for offspring health and can make conception more challenging. However, these risks shouldn’t be overstated—most older fathers have healthy children without complications. What matters is making informed decisions based on good evidence and individual circumstances.

If you’re an older man planning fatherhood, consider testing your fertility, optimising your lifestyle habits, and being realistic about timelines for conception. Open communication with your partner and healthcare providers ensures you’re making the best choices for your future family.

Photo by Filip Mroz on Unsplash

---

---

You May Also Like:

---

Zoom Baby is a leading supplier of Pregnancy Tests and Ovulation Test Kits.