Could where you live affect male fertility?
Written by Sophie Sulehria
When conversations turn to male fertility, the advice is often familiar - we’ve heard it all before! Maintain a healthy weight. Don’t smoke. Limit alcohol. Exercise regularly. Eat a balanced diet.
These lifestyle factors are undoubtedly important and are supported by a growing body of evidence (see my first ESHRE article What I Learned About the Importance of Lifestyle and Nutrition) But new research presented at this year’s European Society of Human Reproduction and Embryology (ESHRE) 2026 Annual Meeting suggests they may not tell the whole story.
A nationwide study from Spain has found striking regional differences in sperm quality, even among men with broadly similar lifestyles.
The findings don’t provide definitive answers about why these differences exist. However, they raise important questions about whether environmental factors, including air pollution, may be playing a greater role in male reproductive health than previously recognised.
As researchers continue to explore why sperm quality appears to be changing worldwide, studies like this add another piece to an increasingly complex puzzle.
Looking beyond individual lifestyle choices
The study analysed fertility assessments from 386 men attending seven assisted reproduction centres across Spain.
Researchers examined a range of measures that fertility specialists routinely use to assess sperm health, including:
Sperm concentration
Motility (how well sperm move)
Morphology (the shape and structure of sperm)
Total motile sperm count
Alongside semen analysis, the team also collected information about lifestyle habits. Importantly, researchers found that lifestyle factors were broadly similar across the different regions included in the study.
Despite that, sperm quality varied considerably depending on where participants lived.
Regional differences that stood out
Perhaps the most striking finding involved total motile sperm count, one of the measures most closely linked with the likelihood of natural conception. Men living in northern Spain recorded an average total motile sperm count of 94.35 million.
For men living in central Spain, the figure was almost half that, averaging 50.11 million.
Researchers also found marked differences in sperm motility.
Reduced sperm motility affected:
23.9% of men in northern Spain
53.4% of men in central Spain
55.4% of men in southern Spain
Significant regional differences were also seen in sperm concentration and morphology.
Taken together, the findings suggest geography may be associated with measurable differences in semen quality.
If lifestyle doesn’t explain it, what does?
One of the reasons this study attracted attention is that the usual explanations didn’t fully account for the findings.
Researchers reported that lifestyle habits - including factors such as smoking, alcohol consumption and other health behaviours - were broadly comparable between regions.
This then naturally raises a new question: If people are living similarly, why are their fertility outcomes different?
The study itself cannot answer that question, but the researchers suggest environmental exposures deserve further investigation.
Air pollution is one possibility. Exposure to certain environmental pollutants has previously been linked with reduced semen quality, increased oxidative stress and hormonal changes that may affect sperm production. However, this study did not directly measure pollution levels or establish a causal relationship. Instead, it identifies an association that warrants further research.
Male fertility is more complex than many realise
For years, discussions around fertility have focused predominantly on women. Yet male factors contribute to around half of all cases where couples have trouble conceiving. Even so, male fertility often receives less attention, both in research and public conversation.
Studies like this reinforce an important message: sperm health is influenced by a complex combination of biological, environmental and lifestyle factors.
While maintaining a healthy lifestyle remains one of the best-supported ways to optimise reproductive health, it may not explain every difference seen between individuals or populations.
That complexity is one reason ongoing research is so important.
The environment is becoming an important area of fertility research
This study fits into a much wider conversation taking place across reproductive medicine. Increasingly, researchers are examining how the environments we live in may influence reproductive health.
Questions are being asked about air quality, chemical exposures, climate, occupational hazards and other environmental factors that were not widely considered a generation ago.
Interestingly, another study presented at this year’s ESHRE meeting explored whether air pollution may alter how sperm genes function, highlighting growing scientific interest in this field.
Taken together, these studies suggest that understanding male fertility may increasingly require looking beyond individual behaviour alone.
What the findings don’t mean
As with any observational study, it’s important not to draw conclusions that go beyond the evidence. This research does not show that living in one region causes lower sperm quality. Nor does it suggest that moving house would improve fertility.
The study included men attending fertility clinics rather than the general population, and while the sample was collected nationwide, it remains relatively modest compared with larger population studies.
Instead, the research highlights patterns that deserve closer investigation. Understanding whether environmental exposures, healthcare differences, occupational factors or other influences contribute to these regional variations will require further work.
Why this matters
Male fertility has often been described as one of the most under-researched areas of reproductive health. While awareness has grown in recent years, there is still much that clinicians and researchers do not fully understand about why sperm quality differs so widely between individuals and populations.
Studies like this help move the conversation forward. Rather than assuming fertility is determined solely by personal choices, they encourage researchers to consider the wider environments in which people live and work. That broader perspective may ultimately help identify new opportunities to protect reproductive health, not just for individuals, but at a population level.
Asking better questions
One of the recurring themes throughout this year’s ESHRE Annual Meeting has been the value of asking better questions. Sometimes research provides clear answers. Sometimes, as in this case, it highlights important gaps in our understanding.
This Spanish study doesn’t solve the mystery of why sperm quality varies between regions. But what it does do is challenge researchers to look beyond traditional explanations and investigate whether environmental factors are playing a larger role than previously recognised.
As male fertility continues to receive the attention it deserves, studies like this remind us that reproductive health is shaped by far more than lifestyle alone. Understanding those influences more fully could help improve fertility care for future generations.