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Unlike women, men do not have a clear end point to their fertility. They continue to produce new sperm throughout their lives and can father children at any age. However, research shows that male fertility does decline gradually with age, particularly after the age of 40. In reality, a typical 45-year-old man is less fertile than a man 10 years younger, with sperm quality beginning to decline as early as 35.
Sperm quality and age
As men get older, the quality of their sperm changes. Semen volume tends to decrease, and there are often fewer moving (motile) sperm and fewer normally shaped (morphologically normal) sperm. Studies also show that sperm from older men are more likely to have DNA damage, with DNA fragmentation in sperm roughly doubling between ages 30 and 45. This can make it harder to achieve a pregnancy and is thought to be linked to increased oxidative stress in the body over time.
Lower testosterone levels in older men may also contribute to reduced libido and erectile difficulties, which can affect a couple’s chances of conceiving naturally.
The role of health and lifestyle
Many health conditions that become more common with age - such as obesity, high blood pressure and type 2 diabetes - can have a negative impact on male fertility. These conditions can alter hormone levels, damage blood vessels, and increase oxidative stress, all of which may affect sperm production and quality.
Lifestyle factors play a big part too. Smoking, drinking excess alcohol, eating a poor diet, or being inactive can all worsen age-related fertility decline. The good news is that these are modifiable factors. Supporting men to maintain a healthy weight, exercise regularly, stop smoking, and limit alcohol can have a positive impact on sperm health.
Fertility outcomes and risks
This age-related decline in male fertility is often overlooked. While many older men do father children, studies show that conception can take longer as paternal age increases. There is also a higher likelihood of needing fertility treatment. Some research suggests a small increase in the risk of pregnancy loss or certain health conditions in children of older fathers, but it’s important to note that the overall risk remains low.
For couples trying to conceive, it’s important that both partners’ health and age are considered during any fertility assessment.
Supporting male fertility
Its not all bad news - research shows that some of this decline can be prevented, or at least slowed, with the right diet and lifestyle.
Nutrition plays an important role in sperm production and protection against oxidative stress. Key nutrients such as zinc, selenium, vitamin C, vitamin E, and L-carnitine contribute to normal sperm development and help protect cells from oxidative damage. These nutrients can be obtained through a healthy, balanced diet or through a targeted preconception supplement.
Key takeaways for healthcare professionals
- Male fertility does decline with age, particularly from around 40 onwards.
- Sperm quality (motility, morphology, DNA integrity) decreases gradually over time.
- Health conditions and lifestyle factors can accelerate this decline.
- Encouraging healthy habits and good nutrition can help optimise sperm quality.
- It’s important to assess and support both partners, not just the woman, when couples present with fertility concerns.
References
Siddighi S, Chan CA, Patton WC, Jacobson JD, Chan PJ. Male age and sperm necrosis in assisted reproductive technologies. Urol Int. 2007;79(3):231-4. doi: 10.1159/000107955. PMID: 17940355.
Singh NP, Muller CH, Berger RE. Effects of age on DNA double-strand breaks and apoptosis in human sperm. Fertil Steril. 2003 Dec;80(6):1420-30. doi: 10.1016/j.fertnstert.2003.04.002. PMID: 14667878.
Moskovtsev SI, Willis J, Mullen JB. Age-related decline in sperm deoxyribonucleic acid integrity in patients evaluated for male infertility. Fertil Steril. 2006 Feb;85(2):496-9. doi: 10.1016/j.fertnstert.2005.05.075. PMID: 16595239.
Wyrobek AJ, Eskenazi B, Young S, Arnheim N, Tiemann-Boege I, Jabs EW, Glaser RL, Pearson FS, Evenson D. Advancing age has differential effects on DNA damage, chromatin integrity, gene mutations, and aneuploidies in sperm. Proc Natl Acad Sci U S A. 2006 Jun 20;103(25):9601-6. doi: 10.1073/pnas.0506468103. Epub 2006 Jun 9. PMID: 16766665; PMCID: PMC1480453.