Scientists and physicians increasingly agree on one point: male fertility appears to be declining in many parts of the world. What remains far less certain is the cause. While social media discussions often focus on specific modern technologies or environmental exposures, experts say the real picture is far more complex.
Demographic data shows that overall fertility rates—the number of babies born relative to the population of women of childbearing age—have fallen across much of the developed world. While many factors influence birth rates, researchers have also examined whether biological changes in male reproductive health may play a role.
Dr. Alex Robles of the Columbia University Fertility Center said clinicians are seeing more cases in which male factors contribute to infertility. According to Robles, roughly one-third of couples seeking fertility treatment show evidence that male reproductive issues are part of the challenge.
Several studies have attempted to measure long-term trends in sperm counts. A widely cited 2017 meta-analysis published in Human Reproduction Update suggested that sperm counts among men in Western countries declined by nearly 60 percent between 1973 and the early 2010s. An updated analysis published in 2023 reported similar findings, reinforcing concerns among some researchers.
One of the study’s authors, epidemiologist Hagai Levine, has warned that declining sperm counts could signal broader environmental health problems. He described the trend as a potential “canary in the coal mine,” suggesting it may reflect wider changes affecting human health.
However, the issue remains controversial within the scientific community. A separate analysis published in 2025 by researchers at the Cleveland Clinic reviewed studies spanning more than five decades and concluded that sperm counts have remained relatively stable overall. Lead author Dr. Scott Lundy emphasized that even moderate changes in sperm counts do not necessarily translate into widespread infertility.
Lifestyle and health factors are widely considered important influences on male fertility. Doctors point to obesity, smoking, poor diet, heavy alcohol use, and marijuana consumption as contributors that can negatively affect sperm production and quality. Improvements in these areas—such as maintaining a healthy weight, exercising regularly, and limiting substance use—may help improve reproductive health.
Medical conditions can also play a role. Systemic inflammation, infections, and certain illnesses may temporarily reduce sperm counts. Lundy noted that even common infections accompanied by fever—such as influenza or COVID-19—can significantly lower sperm production for up to three months.
Experts also emphasize that fertility issues are often misunderstood. While infertility is frequently perceived as primarily a women’s health issue, male factors are involved in roughly one-third to one-half of all cases.
Some potential environmental influences are still being studied. Microplastics and endocrine-disrupting chemicals found in certain plastics and consumer products have raised concern among researchers, though definitive conclusions about their effects on fertility remain limited.
Other widely circulated claims lack strong scientific evidence. For example, concerns that keeping a cellphone in a front pocket significantly harms sperm counts have not been confirmed by current research, although some scientists say the possibility has not been fully ruled out.
Medical specialists generally recommend focusing on well-established health factors rather than unproven remedies. Claims that supplements can dramatically increase sperm counts, for instance, are not strongly supported by scientific data.
When fertility problems arise, doctors often begin with a detailed evaluation that may include semen analysis, hormonal testing, and a review of medical history and lifestyle factors. Advances in reproductive technology are also expanding treatment options, including the use of artificial intelligence and robotic tools in fertility clinics.
