How much can lifestyle factors affect male fertility compared with underlying
Lifestyle choices can significantly influence male fertility, although the extent of their impact often varies when compared with underlying medical conditions. Both categories affect sperm quality largely through oxidative stress, which can damage sperm DNA and increase sperm DNA fragmentation (SDF).
Various lifestyle factors are known to increase oxidative stress within the reproductive system. For example, obesity can promote inflammation, hormonal disturbances, and the production of reactive oxygen species (ROS), all of which may compromise sperm DNA integrity. Exposure to environmental pollutants, heavy metals, cigarette smoke, alcohol, and endocrine-disrupting chemicals has also been linked to higher levels of DNA damage in sperm. Additionally, prolonged periods of ejaculatory abstinence may increase the risk of DNA fragmentation because sperm remain exposed to oxidative conditions for longer periods. Importantly, many of these lifestyle-related effects can be reduced through behavioural changes, such as weight management and limiting exposure to harmful substances.
Underlying medical conditions, however, are often associated with more pronounced and persistent effects on fertility. Ageing is linked to a gradual decline in sperm quality due to increased oxidative damage and reduced efficiency of cellular repair mechanisms. Conditions such as varicocele can impair testicular function by disrupting blood flow and increasing testicular temperature, resulting in elevated SDF levels even in men with otherwise normal semen analyses. Similarly, infections, diabetes, leukocytospermia, and testicular cancers can contribute to sperm DNA damage through inflammatory processes, hormonal disturbances, and excessive ROS production.
Overall, both lifestyle factors and medical conditions can negatively affect male fertility by increasing oxidative stress and sperm DNA damage. However, medical conditions generally have a stronger direct effect on reproductive function, while lifestyle factors may be more modifiable and therefore offer greater opportunities for intervention and improvement.
What are the most common biological causes of male infertility that cannot be corrected through lifestyle changes alone?
The most common biological causes of male infertility that cannot be corrected through lifestyle changes alone are medical conditions that directly affect sperm production, transport, or function. One of the most frequently identified causes is varicocele, a condition characterised by enlarged veins in the scrotum that can impair blood drainage and increase testicular temperature. This condition has been strongly associated with elevated levels of sperm DNA fragmentation (SDF), even in men who present with normal semen parameters (Gill et al., 2021).
Hormonal disorders are another important biological cause of infertility. Disruptions in the hypothalamic-pituitary-gonadal axis can alter the production of hormones required for normal spermatogenesis, resulting in reduced sperm quantity and quality. Unlike lifestyle-related factors, these endocrine abnormalities generally require medical treatment to restore fertility.
Genetic factors can also significantly impair male reproductive potential. Chromosomal abnormalities and genetic defects affecting sperm production often lead to severe reductions in fertility and cannot be resolved through behavioural modifications alone. Similarly, structural abnormalities of the reproductive tract may obstruct sperm transport and require surgical intervention.
Ageing is another biological factor associated with declining male fertility. Research suggests that increasing age is linked to higher levels of oxidative stress, impaired chromatin remodelling, and reduced apoptotic regulation, all of which contribute to increased sperm DNA damage and reduced sperm quality (Vaughan et al., 2020; Petersen et al., 2018).
Infections and inflammatory conditions may also have long-term effects on fertility. Conditions such as leukocytospermia can promote excessive production of reactive oxygen species (ROS), leading to oxidative damage of sperm DNA (Gallegos et al., 2008). Furthermore, diseases such as diabetes and testicular cancer have been associated with elevated SDF through mechanisms involving oxidative stress, endocrine disruption, and cellular damage (Agbaje et al., 2007; Calamai et al., 2023).
Overall, while lifestyle factors can contribute to male infertility, biological conditions such as varicocele, hormonal disorders, genetic abnormalities, age-related changes, infections, diabetes, and testicular cancer often have more direct and persistent effects on reproductive function. These conditions typically require medical diagnosis and treatment because lifestyle changes alone are unlikely to fully correct the underlying cause.
Agbaje, I. M., Rogers, D. A., McVicar, C. M., McClure, N., Atkinson, A. B., Mallidis, C., & Lewis, S. E. M. (2007). Insulin dependent diabetes mellitus: implications for male reproductive function. Human Reproduction, 22(7), 1871–1877.
Calamai, L., et al. (2023). Testicular cancer and sperm DNA fragmentation: current evidence and clinical implications. Andrology, 11(2), 245–255.
Gallegos, G., Ramos, B., Santiso, R., Goyanes, V., Gosálvez, J., Fernández, J. L., & Garrido, N. (2008). Sperm DNA fragmentation in infertile men with genitourinary infection. Fertility and Sterility, 90(2), 328–334.
Gill, K., Jakubik-Uljasz, J., Kups, M., & Kurpisz, M. (2021). The impact of varicocele on sperm DNA integrity and male fertility. International Journal of Molecular Sciences, 22(6), 1–16.
Petersen, C. G., Mauri, A. L., Vagnini, L. D., Renzi, A., Petersen, B., Mattila, M., & Franco, J. G. Jr. (2018). The effects of male age on sperm DNA damage. Reproductive Biology and Endocrinology, 16(1), 1–10.
Vaughan, D. A., Tirado, E., Garcia, D., Datta, V., & Toth, T. L. (2020). Sperm DNA fragmentation and male age: a systematic review. Journal of Assisted Reproduction and Genetics, 37(1), 19–26.
When should men seek fertility testing rather than relying solely on lifestyle modifications?
While maintaining a healthy lifestyle is important for supporting reproductive health, lifestyle changes alone may not address underlying medical or biological causes of infertility. Men should consider seeking fertility testing if they have been trying to conceive for 12 months or longer without success. Earlier assessment is generally recommended if the female partner is 35 years of age or older, in which case fertility evaluation should be considered after 6 months of unsuccessful attempts to conceive.
Fertility testing may also be appropriate in cases of recurrent miscarriage, as emerging evidence suggests that sperm quality, including factors such as sperm DNA fragmentation, may contribute to pregnancy loss even when standard semen parameters appear normal.
In addition, men with a history of conditions that may affect fertility, such as undescended testes, testicular injury, varicocele, previous chemotherapy or radiotherapy, reproductive tract infections, or hormonal disorders, may benefit from earlier assessment. Similarly, if there are concerns regarding sexual function, testosterone levels, or previous abnormal fertility test results, seeking specialist advice may help identify any underlying issues sooner.
A semen analysis is often the first step in male fertility assessment, providing valuable information about sperm health and helping determine whether further investigations or advanced diagnostic testing may be beneficial. Early testing can help couples gain clarity more quickly and ensure that any appropriate treatment or intervention is not unnecessarily delayed.
