All mobile telephones and wireless LAN devices emit microwave radiation at the same frequencies used to cook food. Now scientists are trying to determine whether end users are at risk. "We have evidence of possible genetic damage," says Dr. George Carlo, chairman of Wireless Technology Research LLC (Washington, D.C.), which has been conducting research into cellular telephones for 6 years. His study found that "using mobile phones triples the risk of brain cancer."  Dr. Kjell Hansson Mild in Sweden studied radiation risk in 11,000 mobile telephone users. Symptoms such as fatigue, headaches, and burning sensations on the skin were more common among those who made longer mobile telephone calls. At the same time, there are a growing number of unconfirmed reports of individuals whose health has been affected after chronic, frequent use of mobile telephones, presumably from radiation effects on cells.
There is no evidence so far of mobile phone radiation causing tumor formation or memory impairment in humans. Much more research is needed before any firm conclusions can be drawn. Whatever the effects of using mobile telephones may be in humans, the health risk to an individual user from electromagnetic radiation is likely to be very small indeed, but some individuals may be more prone to radiation side effects than others (http://www.globalchange.com/radiation.htm).
Saunders, S. et al., Wireless IP: Ready or Not, Here It Comes, Data Commun., 28 (12), 42–68, 1999.