Researchers found that being exposed to radio-frequency electromagnetic radiation (RF-EMR) from carrying mobiles in trouser pockets negatively affects sperm quality.
Previous research has suggested that radio-frequency electromagnetic radiation emitted by the devices can have a detrimental effect on male fertility.
A team led by Dr Fiona Mathews, of Biosciences at the University of Exeter in UK, conducted a systematic review of the findings from ten studies, including 1,492 samples, with the aim of clarifying the potential role of this environmental exposure.
Participants in the studies were from fertility clinics and research centres, and sperm quality was measured in three different ways: motility (the ability of sperm to move properly towards an egg), viability (the proportion of sperm that were alive) and concentration (the number of sperm per unit of semen).
In control groups, 50-85 per cent of sperm have normal movement. The researchers found this proportion fell by an average of 8 percentage points when there was exposure to mobile phones.
Similar effects were seen for sperm viability. The effects on 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," Mathews said.
"This study strongly suggests that being exposed to radio-frequency electromagnetic radiation from carrying mobiles in trouser pockets negatively affects sperm quality.
"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," Mathews said.
The results were consistent across in vitro studies conducted under controlled conditions and observational in vivo studies conducted on men in the general population, researchers said.
The study is published in the journal Environment International.