Global research trends in male fertility and environmental factors (2016-2025)： a multi-database bibliometric analysis and cross-validation study
This multi-database bibliometric analysis of global research from 2016 to 2025 reveals a rapidly expanding, interdisciplinary field centered on oxidative stress and environmental factors affecting male fertility, with China and the US as leading contributors and future directions pointing toward epigenetic mechanisms, emerging pollutants, and biomarker development.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of a preprint that has not been peer-reviewed. It is not medical advice. Do not make health decisions based on this content. Read full disclaimer
For decades, a quiet but steady decline has been observed in the reproductive health of men across the globe. While many factors influence fertility, from genetics to lifestyle, a growing body of evidence points to the world we live in as a primary driver of this change. The air we breathe, the chemicals in our food, and the materials surrounding our daily lives are not just passive backdrops; they are active agents that can interfere with the delicate biological processes required to create life. Specifically, researchers have long suspected that environmental toxins disrupt the body's hormonal systems and damage the cells responsible for making sperm. This is not merely a matter of individual health but a public concern, as nearly half of all infertility cases involve male factors, and the ability to conceive is a fundamental aspect of human continuity.
To understand the full scope of this issue, a team of researchers from China and the United States undertook a massive review of scientific literature published between 2016 and 2025. They did not simply read a few studies; they analyzed nearly five thousand documents, using advanced computer tools to map out how scientists around the world are thinking about this problem. Their goal was to see the big picture: who is doing the research, what topics are capturing the most attention, and where the field is heading. By looking at thousands of citations and connections between studies, they could identify the core mechanisms that link environmental exposure to male infertility, moving beyond isolated findings to a unified understanding of the crisis.
The analysis revealed that this field of study has exploded in recent years, with the number of published papers and the attention they receive rising sharply. Two nations, China and the United States, emerged as the twin engines driving this global effort, producing the vast majority of the research. While these two countries lead in volume, the work is deeply interconnected, with European institutions acting as a crucial bridge that links researchers across the globe. The study confirmed that this is not a narrow field confined to one type of science; instead, it sits at the intersection of environmental science, toxicology, and reproductive biology. The most influential journals in the field are those that specialize in how chemicals affect health and how the body reproduces, signaling that the scientific community views this as a critical area of inquiry.
When the researchers looked closely at what these thousands of studies were actually saying, a clear pattern emerged. The central theme connecting almost all the work is oxidative stress. In simple terms, this is a state where the body produces too many unstable molecules that can damage cells, much like rust forming on metal. The research shows that when men are exposed to environmental pollutants, their bodies often struggle to manage this damage, leading to a decline in sperm quality and function. This mechanism acts as a common thread, linking diverse threats ranging from heavy metals and air pollution to the chemicals found in plastics.
Among the specific threats identified, endocrine-disrupting chemicals, particularly a substance called bisphenol A (BPA), have been the most studied. BPA is a chemical used widely in the manufacturing of plastics and resins, and it can mimic the body's natural hormones, confusing the signals that tell the body how to produce sperm. The data shows that exposure to BPA is linked to lower sperm counts and reduced motility. However, the focus of research is shifting. While BPA remains a major concern, scientists are increasingly turning their attention to newer, emerging pollutants. These include microplastics—tiny fragments of plastic found everywhere from the ocean to the air—and per- and polyfluoroalkyl substances, often known as PFAS. The studies suggest that these newer contaminants are just as dangerous, if not more so, because they can penetrate the body's protective barriers and cause damage at a cellular level.
The review also highlighted a significant shift in how scientists are thinking about the long-term consequences of this exposure. It is no longer enough to ask how pollution affects a man's current fertility; researchers are now investigating how these exposures might harm the health of his children and even his grandchildren. This concept, known as transgenerational inheritance, suggests that environmental damage can alter the genetic instructions passed down to future generations. The analysis found that the field is moving toward understanding these deep, multi-generational effects, driven by the realization that the damage done today may echo for decades.
Looking ahead, the researchers identified three clear paths for the future of this field. First, there is an urgent need to understand the specific molecular switches that turn environmental exposure into genetic damage, particularly how these changes are passed down. Second, scientists must study the complex mixtures of pollutants that people actually encounter in real life, rather than just testing single chemicals in isolation. Finally, the field must develop better ways to detect early signs of damage before it becomes irreversible, creating tools that can warn at-risk populations and guide interventions. The work done in this review provides a roadmap, showing that while the challenge is complex and the threats are pervasive, the scientific community is rapidly building the knowledge needed to protect reproductive health for generations to come.
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