Between 30 and 50% of men of fertile age have low-quality semen. In fact, in the last fifty years, an increase in the decrease in semen quality has been observed; has decreased from an average of 99 million sperm per milliliter to 47 million per milliliter. While several environmental and lifestyle factors have been proposed to explain this decline.
This phenomenon is believed to be the result of a combination of environmental factors (endocrine disruptors, pesticides, radiation) and lifestyle habits (diet, alcohol, stress, smoking). Stress, some medications or practicing high-intensity sports are also some of the agents that are known to harm sperm quality. But what about mobile phones? For years, the electromagnetic radiation emitted by these phones has been pointed out as a risk to semen quality.
Semen quality is determined by the evaluation of parameters such as sperm concentration, total sperm count, sperm motility and sperm morphology. According to values established by the World Health Organization (WHO), it will most likely take more than a year for a man to conceive a child if his sperm concentration is less than 15 million per milliliter. Furthermore, the percentage chance of pregnancy will decrease if the sperm concentration is less than 40 million per milliliter.
Could the cell phone be to blame? A team from the University of Geneva (UNIGE), in collaboration with the Swiss Institute of Public and Tropical Health (Swiss TPH), has published an important cross-sectional study on the subject, concluding that frequent use of mobile phones is associated with lower sperm concentration and total sperm count.
The study is based on data from 2,886 Swiss men between 18 and 22 years old, recruited between 2005 and 2018 at six military recruitment centers. The scientists studied the association between the semen parameters of these men and their mobile phone use.
The mean sperm concentration was significantly higher in the group of men who did not use their phone more than once a week (56.5 million/mL) compared to men who used their phone more than 20 times a day (44 .5 million/mL). This difference corresponds to a 21% decrease in sperm concentration for frequent users (>20 times/day) compared to infrequent users (<1 time>).
“The men completed a detailed questionnaire related to their lifestyle habits, their general health and, more specifically, how often they used their phones, as well as where they placed them when not in use,” explains Serge Nef, professor head of the Department of Genetic Medicine and Development of the UNIGE Faculty of Medicine and the SCAHT – Swiss Center for Applied Human Toxicology, who co-directed the study.
However, the results of the study, published in Fertility and Sterility, show that the researchers found no association between mobile phone use and low sperm motility and morphology.
The researchers noted that this inverse association was most pronounced in the first study period (2005-2007) and gradually decreased over time (2008-2011 and 2012-2018). “This trend corresponds to the transition from 2G to 3G and then from 3G to 4G, which has led to a reduction in the transmission power of phones,” explains Martin RÖÖsli, associate professor at TPH Switzerland.
Analysis of the data also appears to show that the position of the phone (e.g., in a pants pocket) was not associated with lower semen parameters. “However, the number of people in this cohort who indicated that they did not carry their phone close to their body was too small to draw a really strong conclusion on this specific point,” adds Rita Rahban, principal investigator and teaching assistant in the Department of Medicine. Genetics and Development of the Faculty of Medicine of UNIGE and SCAHT, first author and co-director of the study.
This study, like most epidemiological studies investigating the effects of mobile phone use on semen quality, was based on self-reported data, which is a limitation. In doing so, the individual’s reported frequency of use was assumed to be an accurate estimate of electromagnetic radiation exposure. To address this limitation, a study funded by the Federal Office for the Environment (FOEN) was launched in 2023, from which more conclusive results are expected.
The goal is also to better describe the mechanism of action behind these observations. “Do the microwaves emitted by mobile phones have a direct or indirect effect? Do they cause a significant increase in temperature in the testicles? Do they affect the hormonal regulation of sperm production? All this remains to be discovered,” concludes Rita Rahban.