• Posted November 1, 2023

Could Cellphones Be Harming Men's Sperm?

Cellphone use might be blunting a fellow's chances of becoming a father, a major new study reports.

Young men who frequently use mobile phones have lower sperm concentrations and sperm counts than guys who rarely dial on the go, Swiss researchers found using more than a decade's worth of data.

However, the data also showed that the move to improved cell technologies like 4G could have the happy side effect of protecting male fertility, the study authors noted.

The association between cellphone use and lower semen quality gradually decreased between 2005 and 2018, the researchers found.

"We think that this trend corresponds to the transition from 2G to 3G, and then from 3G to 4G, which has led to a reduction in the transmitting power of phones,"said lead researcher Rita Rahban. She's a senior researcher and teaching assistant in the University of Geneva's department of genetic medicine and development.

"4G is much more efficient than 2G in data transmission, which reduces exposure time,"Rahban explained. "In general, newer generations of mobile technology, like 4G and 5G, aim to reduce radiation exposure while offering improved data speeds and capabilities."

Overall, the investigators found that men who used their cellphones more than 20 times a day were 30% more likely to have a sperm concentration lower than the value set by the World Health Organization (WHO) for minimum healthy male fertility, compared to men who used their mobile less than once a week.

Frequent cell users also were 21% more likely to have a sperm count lower than the WHO's fertility reference, compared to rare users.

These observed effects on sperm concentrations and counts "could impact a man's fertility,"said Dr. Ranjith Ramasamy, director of male reproductive medicine and surgery at the University of Miami Health System.

"Their findings challenge previously held notions and prompt us to reconsider our understanding of mobile phone effects on male fertility,"said Ramasamy, who was not involved in the study.

Given these findings, cellphones might be one reason why many studies have shown that semen quality has decreased.

Average sperm count is reported to have dropped from 99 million sperm per milliliter of semen to 47 million/mL during the past 50 years, the researchers said in background notes.

For the study, Rahban and her colleagues tracked nearly 2,900 Swiss men aged 18 to 22 recruited between 2005 and 2018 at six military conscription centers.

The men completed detailed questionnaires about their lifestyles and health, including their cellphone use. They also provided sperm samples as part of a physical examination.

Average sperm concentration in men who use their cellphone more than 20 times a day was 44.5 million/mL, compared to 56.5 million/mL for men who don't use their cellphone more than once a week, Rahban said.

"This difference corresponds to a 21% decrease in sperm concentration for frequent users compared to rare users,"Rahban said.

Heavy mobile phone users also had a lower average sperm count, about 120 million compared to nearly 154 million for men who rarely use a cellphone.

Overall, heavy cellphone users were more likely to have a sperm concentration that dips below 15 million/mL, which the WHO says is the level at which a man will probably take more than a year to conceive a child, according to the report.

But the researchers warned that their study did not evaluate the effect of mobile phone use on pregnancy rates, and could not draw a direct cause-and-effect link between cellphones and male infertility.

"What we can say is just that the risk of having low sperm concentration is higher in the group of men frequently using their phones,"Rahban said.

Rahban also pointed out that the average sperm concentration for heavy cellphone users of 44.5 million/mL still is more than two times higher than the WHO's value of 15 million/mL for male infertility.

"Therefore, the risk for men to be infertile because of mobile phone use is low,"Rahban said. "It is important to mention that sperm are produced continuously in the testicles every 10 weeks. Men, therefore, renew their sperm storage quite frequently. This means that even if we find an association, the effect is in many cases reversible. Men should not be scared."

Cellphone use did not affect the shape of sperm or their ability to move, the findings showed.

Ramasamy agreed that "the exact extent to which this would prevent pregnancy would require further studies, including those that directly link these sperm changes to successful pregnancy rates."

There are a couple of possible reasons why cellphone use might harm semen quality, the experts said.

An obvious possibility is the heat generated by phones.

"When a mobile phone operates at its highest power, it can cause local tissue temperature to rise. If a phone is stored in a pants pocket near the testes, this slight increase in temperature could potentially interfere with sperm production and development,"Ramasamy said.

"However, no solid evidence supports this direct effect, as no direct correlation has been found between phone positioning on the body and sperm quality,"he stressed.

In this study, "we did not observe any association between low semen quality and placing the phone in the pant pocket,"Rahban said.

Another possibility is that the electromagnetic radiation emitted by cellphones could interfere with the hypothalamic-pituitary-gonadal axis, the brain-gland connection that regulates testicular function and sperm production, Rahban and Ramasamy suggested.

"Various proposed mechanisms have tried to explain these potential adverse effects, including disruptions in cellular metabolism, DNA damage, oxidative stress, and thermal actions,"Ramasamy said.

"However, it's essential to note that many of these studies have been based on rodent models or examined human semen outside the body, which doesn't necessarily reflect real-life human exposure,"he continued.

The new study was published Oct. 31 in the journal Fertility and Sterility.

More information

The Environmental Working Group has more about cellphone radiation and male fertility.

SOURCES: Rita Rahban, PhD, senior researcher and teaching assistant, department of genetic medicine and development, University of Geneva; Ranjith Ramasamy, MD, director, male reproductive medicine and surgery, University of Miami Health System; Fertility and Sterility, Oct. 31, 2023