Mobile phone Radiation from mobile phones do harm body cells and damage DNA, a laboratory study has shown.
The four-year Reflex study, co-ordinated by the German research group Verum, studied the effects of radiation on animal and human cells in a laboratory.
They found that, after being exposed to electromagnetic fields, the cells showed a significant increase in DNA damage which could not always be repaired by the cell.
Damage was also seen in the next generation of cells. Mutated cells are seen as a possible cause of cancer.
The study, which has not been published in a journal, also reported other harmful effects on cells.
The radiation used in the study was at Specific Absorption Rate (SAR) levels of between 0.3 and 2 watts per kilogram.
The SAR is the rate at which the body absorbs emissions from the phone handset.
Most phones emit radio signals at SAR levels of between 0.5 and 1 W/kg.
Mobile phones cannot be sold to unless they fall within the SAR of 2 watts per kg.
Franz Adlkofer, who led the Reflex study, said people should use landlines, rather than mobiles, wherever possible.
He added: "We don't want to create a panic, but it is good to take precautions."
He said definitive research would take another four to five years.
Other studies have suggested mobile phone radiation may have some effect on the body, such as heating up body tissue and causing headaches and nausea, but no study that could be independently repeated has proved that radiation had permanent harmful effects
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The results of this study are preliminary, not yet published or peer reviewed and require further replication by other groups 
