Increased mobile phone use has been linked to lower sperm concentration and total sperm count in a cohort of young men.

Despite concerns about the effect of electromagnetic radiation produced by mobile phones on sperm count and quality, repeat studies have reported conflicting findings. A study of a cohort of young Swiss men has now found a significant association between increased daily mobile phone use and risk of having a sperm count and concentration below standard fertile levels.

'Previous studies evaluating the relationship between the use of mobile phones and semen quality were performed on a relatively small number of individuals, rarely considering lifestyle information, and have been subject to selection bias, as they were recruited in fertility clinics. This has led to inconclusive results', Rita Rahban senior researcher and teaching assistant at  the University of Geneva the Swiss Centre for Applied Human Toxicology, and first author of the paper, told the Independent.

A cohort of 2886 Swiss men, aged 18-22 years, were recruited between 2005 and 2018 in six centres around Switzerland during their military enrolment. They provided a semen sample and answered a health and lifestyle questionnaire, describing how often they used their mobile phones and where they were kept when not in use. Men who reported using their phones more than 20 times a day had 21 percent lower sperm concentration and 22 percent decrease in total sperm count compared to men who used their phone no more than once a week. They also had a 30 percent and 21 percent increased risk for sperm concentration and total sperm count to be below standard fertility levels.  

Researchers found that the negative association between semen quality and mobile phone usage weakened over the course of the study period: the strongest association was between 2005-2007, which declined in 2008-2011 and further in 2012-2018. This finding aligned with the shift from 2G through to 4G, each shift known to reduce the electromagnetic radiation produced by a mobile phone. The paper published in Fertility and Sterility also explained that there was no association drawn between semen quality and where the phone was kept, such as a trouser pocket.

'[This] study is a little step forward in the debate…' said Professor Allan Pacey, an andrologist from the University of Manchester and PET (Progress Educational Trust) trustee, who was not involved in the research. 'However, we should be cautious about its interpretation as it only shows an association between mobile phone use and semen quality. We cannot be sure that the mobile phone is not a surrogate marker for another aspect of the men's lifestyle or occupation that is the real cause of any changes to their sperm quality.'