Scientists and doctors agree that there is a general decline in male fertility, but they are not sure why.
Social media buzz has pointed to a few environmental exposures as possible factors, including cell phones and electric cars.
But the reality is “more complex” than that, according to experts who spoke to them recently National Geographic.
Although it is not clear whether the decline is at a point that should be considered a crisis, the numbers show that total fertility – measured demographically by the number of children born compared to women of reproductive age – has declined.
Dr. Alex Robles of the Columbia University Fertility Center in New York emphasized that clinical practitioners are “definitely seeing more couples where the male factor contributes to infertility.”
“At least a third of the couples we evaluate have some masculine element,” he told Fox News Digital.
A 2017 meta-analysis published in The Oxford Journals: Human Reproduction Update found that sperm counts in Western countries have declined by approximately 60% globally since 1973. A 2023 update confirmed these same findings.
The study’s lead author and epidemiologist Hagai Levin warned that this trend could lead to human extinction if not addressed.
“This is the canary in the coal mine,” Levin, a public health physician at the Hebrew University-Hadassah Brown School of Public Health, told National Geographic. “It shows that there is something very wrong with our current environment, as low sperm counts predict disease and mortality.”
However, these results have been contradicted by other studies. A 2025 Cleveland Clinic analysis of studies over the past 53 years found that sperm counts are stable.
“There is no evidence to suggest that this decrease is the cause of the severe decrease in the ability to cause pregnancy,” primary study author Scott Lundy, MD, a reproductive urologist at the Cleveland Clinic, told National Geographic. “Most men, even with a modest decrease in sperm count, will have no problems conceiving.”
Potential factors for decline
Robles noted that multiple lifestyle factors can lead to decreased male fertility, including obesity, smoking and diet, as well as environmental exposures and delayed fatherhood.
National Geographic also reported that heavy drinking and marijuana use directly contribute to decreased fertility, and that quitting these habits, while also exercising and losing weight, can help.
Systemic inflammation, infection and disease can also have a “significant and profound impact on the current status of fertility,” Lundy told National Geographic.
Those who have a fever due to an infection, such as flu or Covid, will have “drastically lower” sperm counts for three months, he said.
Male infertility can also be a sign of overall health, according to Robles. “Poor semen indicators are associated with other medical conditions and may indicate underlying metabolic, hormonal or environmental problems,” he told Fox News Digital.
Alan Pacey, deputy dean of the School of Biology, Medicine and Health at the University of Manchester, told National Geographic that this decline could be due to increased use of contraception, as well as men waiting longer to have children or choosing not to have them at all.
Microplastics have also been raised on social media as a possible cause, but the effects are unclear, according to experts.
Lundy revealed to National Geographic that there is some evidence of endocrine disrupting chemicals — substances found in reusable plastics and some disposable products — that alter men’s fertility.
Myths have been broken
Concerns have spread on social media that keeping a mobile phone in the front pocket could harm men’s fertility. While Lundy said such an effect is biologically possible, there is currently no scientific evidence to support this claim.
Another common myth is that infertility is mostly a female problem, but male factors contribute to about a third to half of all cases, Robles noted.
The claim that taking nutritional supplements can boost sperm count is another common myth, he said, adding that it is not supported by strong scientific evidence.
“Men should focus on the factors we know are important: maintaining a healthy weight, avoiding tobacco, limiting alcohol, and managing chronic health conditions,” Robles advised.
Experts recommend seeing a urologist to address fertility concerns. Robles said his approach begins with evaluation, semen analysis, hormonal testing, and medical history, while also exploring lifestyle factors.
In addition to traditional treatment options, Robles said his fertility center also uses advanced tools including artificial intelligence and robotics.
“Such technologies expand options for patients who previously had very limited paths to biological parenthood,” he said.