Paternal Age and Trying to Conceive: Sperm Quality, Pregnancy and the Baby

When age and fertility come up, attention tends to focus on the woman's age. In fact, research suggests that a man's age may also influence reproductive capacity and the health of a future child. In this article I want to talk, calmly and objectively and on the basis of evidence, about how advanced paternal age may affect trying to conceive and giving birth.

Please note that much of what I describe here comes from basic research, including cell and animal studies, and effects in humans have not been established.

What Is Advanced Paternal Age?

The term advanced paternal age is generally used when a man wishes to have children beyond a certain age. There is no single clear definition, but many studies use 35, 40 or 45 years and older as the cut-off. It is well known that a woman's age has a large bearing on how easily pregnancy occurs; male reproductive capacity may also change with age.

Possible Effects of Advanced Paternal Age on Sperm

Research suggests that as men grow older, several changes may occur in sperm quality.

DNA Damage in Sperm

It has been noted that damage to sperm DNA may become more likely with advancing age. DNA damage may affect the development of the fertilized egg and implantation, and it has been considered as a possible contributor to a higher risk of miscarriage and to infertility. These effects are complex, however, and they do not necessarily occur in every older man.

Changes in Semen Quality

Multiple studies have reported that semen parameters such as semen volume, sperm concentration and sperm motility may decline gradually as men age. The extent of these changes varies widely between individuals, and a decline in semen quality does not mean that natural conception becomes impossible. What matters is simply recognizing that such changes are possible.

Effects on Trying to Conceive

Several studies have also examined how advanced paternal age may affect the process of trying to conceive.

The Likelihood of Natural Conception

With advanced paternal age, it has been suggested that the time taken to achieve natural conception may be longer. This is thought to reflect several interacting factors, including changes in sperm quality and a reduction in the frequency of intercourse. Because these effects are strongly shaped by the woman's age and by other health factors, it is considered difficult to evaluate the influence of paternal age on its own.

Outcomes with Assisted Reproductive Technology (ART)

There is a meta-analysis here, pooling 28 studies and 32,484 cycles (PMID: 35690546). It analyses 16 studies using the patient's own oocytes and 12 using donor oocytes separately.

In autologous cycles, paternal age under 40 was associated with:

Clinical pregnancy rate, odds ratio 1.65 (95% CI 1.27–2.15)
Live birth rate, odds ratio 2.10 (95% CI 1.25–3.51)
Miscarriage rate, odds ratio 0.74 (95% CI 0.57–0.94), i.e. lower

The donor oocyte cycles are the important part. With donor oocytes, maternal age is controlled, which means the effect of paternal age can be separated out on its own. There too, paternal age under 50 was associated with a lower miscarriage rate (odds ratio 0.68, 95% CI 0.54–0.86), a higher blastocyst rate (1.61, 1.08–2.38) and more cleavage-stage embryos (1.67, 1.02–2.75).

So it is not the case that "maternal age dominates, so the effect of paternal age cannot be isolated." Even in a design where maternal age is held constant, paternal age is associated with outcomes.

That said, this pools observational studies and does not establish causation. Whether age itself is the cause, or something that changes alongside age, is not separated by this analysis.

Effects on the Baby

Research has also looked at whether advanced paternal age may have particular health implications for the child. These risks are very rare, however, and the overall effect on children born is considered limited.

Genetic Risks

In advanced paternal age it has been suggested that new mutations in sperm DNA may increase, and that this may slightly raise the risk of rare inherited conditions and certain congenital disorders. These risks remain at a very low level, and in the great majority of cases children are unaffected.

Risks Relating to Development

Some studies have suggested an association between advanced paternal age and the risk of neurodevelopmental conditions such as autism spectrum disorder and schizophrenia. These associations are complex, and causation has not been clearly established. Environmental factors and other genetic factors are thought to be substantially involved as well.

What Matters Most: Open Conversation with Your Partner, and Overall Health

For anyone already feeling a vague anxiety about future pregnancy and childbirth, information about advanced paternal age may become one more source of worry. Most of the risks discussed below are rare. The ART finding above is the exception: it comes from a large pooled analysis, and it holds up in the design that controls for maternal age. More than anything, what matters is talking openly with your partner about this information and respecting each other's feelings.

Rather than being overwhelmed by uncertain information, it helps to keep a realistic perspective. You can find more detailed information about trying to conceive on this site.

What We Can Do: A Healthy Lifestyle

At present there is no certain way to eliminate entirely the risks that may accompany advanced paternal age. A generally healthy lifestyle, however, is thought to help maintain sperm quality and to support reproductive capacity overall.

A balanced diet: aim to include plenty of vegetables and fruit rich in antioxidants. That said, there is no established scientific basis for the idea that any particular food or supplement dramatically improves fertility on its own.
Moderate exercise: because obesity may adversely affect sperm quality, moderate exercise to maintain a healthy weight is worthwhile.
Avoiding smoking, limiting alcohol: smoking and heavy drinking have been noted as possible contributors to the risk of sperm DNA damage.
Stress management: because stress may affect hormone balance, it is important to find ways of easing it that suit you.
Regular health check-ups: finding and addressing underlying health problems early matters not only for conception but for overall health. I also discuss the importance of preconception care on the home page.

These measures are recommended for basic health maintenance in every couple trying to conceive, regardless of the father's age.

Frequently Asked Questions (FAQ)

1. From what age is a man considered to be of advanced age?

The clear definition differs between studies, but many use 35, 40 or 45 years and older as the cut-off. This only describes a statistical tendency; an individual man's reproductive capacity is not determined by age alone.

2. Is it still possible to have a healthy child at an advanced paternal age?

Yes. The risks to the child discussed above are rare events, and most are not established as causal. Even where a slight statistical increase is seen, most older fathers have healthy children. The ART findings are a separate matter: they concern the odds within a treatment cycle, not the health of a child once born.

3. Are there steps an older man can take when trying to conceive?

Maintaining a generally healthy lifestyle is the most important thing: a balanced diet, moderate exercise, not smoking, limiting alcohol and managing stress. There is no particular magic solution, but these habits help support sperm quality and promote overall health. If you are worried, talking with a specialist is also useful.

Summary

The association between paternal age and ART outcomes has been shown in a pooled analysis of 28 studies and 32,484 cycles. What matters is that the association persists in donor oocyte cycles, where maternal age is held constant — so the explanation that "the woman's age dominates, so paternal age cannot be assessed" does not fit this data.

The items concerning the child's health are a different matter: those are rare events, and most of the associations are not established as causal. That is the part where excessive anxiety is not warranted.

What matters is sharing the information with your partner and looking after the basics of health. If you have worries or questions, talk them through with a specialist.

References

Does advanced paternal age affect outcomes following assisted reproductive technology? A systematic review and meta-analysis. Reprod Biomed Online. 2022. PMID: 35690546 (28 studies, 32,484 cycles; in the donor oocyte subgroup maternal age is controlled, allowing the effect of paternal age to be separated out; pools observational studies and does not establish causation)