Around 14% of couples in high and middle income countries have difficulty conceiving, and several countries are seeing unexplained declines in semen quality. Now a new review of published evidence suggests one explanation could be men carrying their cell phones in their trouser pockets.
Men may not realize it, but they could inadvertently be reducing their fertility through exposure to radio-frequency electromagnetic radiation (RF-EMR), suggest researchers from the University of Exeter in the UK, who report their findings in the journal Environment International.
Led by Dr. Fiona Mathews, senior lecturer in mammalian biology and program director for biosciences and animal behavior at Exeter, the team carried out a systematic review of 10 studies that had measured exposure to cell phone RF-EMR and had tested semen samples.
Altogether the pooled data covered results from nearly 1,500 semen samples obtained from men attending fertility clinics and research centers.
The researchers analyzed three measures of sperm quality: motility (the ability of sperm to move properly towards an egg), viability (the proportion of live sperm) and concentration (the number of sperm per unit of semen).
Sperm from control groups showed 50-85% motility. But this fell by an average of 8% in samples where there had been exposure to cell phones, noted the researchers, who found similar effects for sperm viability. However, the results for sperm concentration were less clear.
"Given the enormous scale of mobile phone use around the world, the potential role of this environmental exposure needs to be clarified," says Dr. Mathews.
Findings could be important for men on borderline of infertility
She adds that the findings "strongly suggest" exposure to radio-frequency electromagnetic radiation from carrying cell phones in trouser pockets has a negative effect on sperm quality, and that:
Sperm motility fell by an average of 8% in samples where there had been exposure to cell phones.
"This could be particularly important for men already on the borderline of infertility, and further research is required to determine the full clinical implications for the general population."
The researchers note that the results are consistent across studies that tested the effects in the lab under controlled conditions (in vitro studies) and studies conducted on men in the general population (in vivo).
They conclude that evidence from further long-term studies, "using standardized levels and periods of exposure, ideally a randomized controlled trial in the general population, is needed to assess the importance of mobile phone exposure to public health."
Meanwhile, Medical News Today recently learned of a study that found a link between being stressed and reduced semen quality in men. While that study did not investigate the underlying reasons, the researchers speculated one reason could be that stress activates the release of glucocorticoids - hormones that influence carbohydrate, fat and protein metabolism - which in turn could reduce testosterone levels and sperm production.