User manuals for the most popular phones tell users not to place devices directly against their bodies but the advice is often buried in the small print.
Research into the potential danger caused by mobiles have proved inconclusive, but some studies have suggested an effect on the brain and on sperm quality.
Alasdair Philips, of Powerwatch, an independent group which investigates the safety of mobile phones, told the Daily Mail: “Most people have no idea about these warnings.
“The safety advice should be included on the boxes and far more prominently in the “getting started” section of user guides and not just in the detail at the back that hardly anyone reads.”
Meanwhile Dr Devra Davis, a leading US scientist, has warned that if the health risks are ignored we could face a “global public health catastrophe” within three years
Mobile phones are low-powered radio frequency transmitters which produce microwave radiation.
Dr Davis, who was part of a team that won the Nobel Peace Prize in 2007, has warned that the threat from this radiation has been underplayed.
Her book Disconnect: The Truth About Cell Phone Radiation, What The Industry Has Done To Hide It And How to Protect Your Family, includes supporting research from studies in the U.S., Sweden, Greece, France and Russia.
A team at the University Of Washington found that just two hours of mobile phone-level radiation splintered the DNA of brain cells in rats, making them similar to cells found in malignant tumours.
In Moscow, a study has found that children who regularly use mobile phones have poorer memories and other learning problems.
Research in seven countries, including the U.S., China and Australia, suggests that keeping a switched-on mobile in a trouser pocket can effect sperm count.
Manuals for the latest BlackBerry (the Torch), warn users to ‘use hands-free operation if available and keep the device at least 25mm from your body (including the abdomen of pregnant women and the lower abdomen of teenagers)’ when it is switched on.
Apple tells iPhone users to keep them 15mm away from their body and to point the dock connection towards their shoulders ‘to increase separation from the antenna’.
The Nokia C6 says phones should either be used at the ear of 15 mm away from the body and that accessories should not contain any metal.
Dr Davis said that people should start keeping phones in bags and the knee-level pockets of cargo trousers, well away from their ovaries or testicles.
Telegraph UK