This is what Wikipedia says about it:

The risk of electromagnetic radiation coming from mobile phones, both the devices as the masts, is still unclear. On the one hand, there does not exist an article that unambiguously proves any health risks. But there is not yet a research about all the effects – in particular, because there has not been enough epidemiological research about prolonged exposure to low doses. [9] An overview of SAR-values [10] displays how much electromagnetic radiation penetrates the body per mobile phone. There is no unambiguously evidence that high SAR-values are harmful for the health and/or a lower SAR-value are less harmful for the health.

According to the epidemiologist and publicist Devra Davis the mobile phone-industry features a fund of 250 million dollar to respond adequately to the industry’s negative research results (wargaming the science).

Health risks of electromagnetic radiation

  • Some people believe that long-term usage of the mobile phone can lead to permanent eye problems and even into a cataract. Scientist from the faculty of medicine of the Israeli institute for technology, exposed the eyelids from young calf to the heat similar to the temperature rise humans experience after a long mobile-phone conversation and to microwave radiation equal to the radiation produced by a mobile phone. After two weeks, it was clear that it has led to a small bump on the eye tissue of the experimental animals, which has very strong similarities to the first face of the serious eye disease cataract.
  • A study of Prof. Santini[14] found a clear increase of the following symptoms in humans that live close to a transmission mast: headaches/migraine, sleep disorders, irritation sensitivity, depressive complains, fatigue, concentration problems, feelings of discomfort and memory disorders. Recent – independent – studies from Austria by Hutter et al. and from Spain by Navarro et al. come to similar findings. At levels from 10-100 μW/m²2 there is a higher change of the named symptoms, while many people are exposed to multiple thousands μW/m²2.
  • Research of the Radbout University in Nijmegen and the company Brainclinics, in which 300 people were being watched during 2 to 3 years, gives proof that people who often make long phone calls, show a drastic delay in the brain functionality compared to people that don’t make these long phone calls, and these differences are not because of different personalities. The effects shown are within the boundaries of being ‘normal’, and the regular callers show an improved capability of focused attention, compared to people calling less often. Because of this, it’s not certain this is a case of adverse health effect.
  • In the research of the scientist Dirk Adang of the university catholique de Louvain, a group of laboratory rats was exposed to cell phone-, antenna- and wifi radiation, and another group wasn’t. The group of exposed rats had double the mortality rates of the group that wasn’t exposed. Of the seventeen exposed rats sixteen died to a tumor. It was a “long-term” research with little exposure. The exposure factor was from the “ICNIRP”.
  • Official researches and measurements, as described on the website of the government Antenna Bureau, there have yet to be shown any health risks from electromagnetic fields. There is no evidence to think otherwise about cell phone- or UMTS radiation.
  • Research of the International Commision on Non-Ionizing Radiation Protection shows that there has not been any causal link between exposure to radiowaves and congestion complaints.
  • Information from the World Health organization shows that there is no evidence of any additional effects of radio waves, just a small body temperature increase when exposed to very high radiation doses.
  • Notifications about a growing number of cases of cancer around transmission masts in the media creates unrest. It’s a fact that cases of cancer are geographically unevenly divided among the population. Because there are transmission masts everywhere it seems logical to expect a cluster of cases of cancer surrounding a transmission mast now and then. In addition the cases of cancer that have been reported are of various types of cancer which have various characteristics. That’s why is seems unlikely that they all have a common cause (for instance a nearby transmission mast).
  • An extensive British research, where 900 people with brains tumors and 1700 healthy people were questioned, no connection was found between mobile calling and brain tumors.
  • Electromagnetic radiation is only able to influence an atom above a certain line (ionizing). This line is at 3,28 x 1015Hz, which corresponds to ultraviolet light. Cell-phones function at a frequence that’s about a million times lower. UMTS for example uses frequencies till 2GHz, cell-phones are much lower than this, so there is talk of ionizing radiation. Although it’s known that low energy not-ionizing radiation can cause a slight temperature increase, there is no statement known about how such radiation could damage the DNA (and could cause cancer).
  • A commision of the health council notes in a rapport (2009/2010) about the research of Dirk Adang (see clues for health risks) that because of various imperfections in the performance of the research and in the static analysis of the data, the conclusions are not scientifically sustainable.

A clearly stated risk of the mobile telephony that, however does not relate to electromagnetic radiation, is calling whilst driving. Who does not use hands-free calling has a five times bigger chance to be in an accident. Hands-free calling is a little less dangerous, but the chance is still 3,8 times as big.[29] Calling whilst driving influences the driving skills possible ever more than a couple glasses of alcohol.

When someone is calling from a car or some other place in which a lot of metal is present, the radiation from a cell-phone will increase drastically as a result of a stronger sending signal. Also the signal goes to various transmission posts because you are moving. Calling whilst driving could possible strengthen the negative effects of radiation.