A study conducted by the International Telecommunications Union has established that almost four billion people worldwide use mobile phones. That's nearly two-thirds of the Earth's population. The safety of mobile phones has been debated for quite some time but the scientists still haven't reached a final conclusion, although evidence is starting to show that cell phones might pose a threat to our health.

Each cell phone has a small radio transmitter inside, used to communicate with the telephone network. Scientists have been trying to establish if the radio frequency of that transmitter is harmful to people, so recently a U.S. Senate subcommittee, formed a team of experts to find out if more research is needed on this matter.

Mobile phones were quite expensive not so long ago but today anyone can afford one and we take them for granted, as subcommittee chairman Tom Harkin, an Iowa Democrat said. “I would venture to guess that almost everyone in this room uses a cell phone on a regular basis, and most of us don't give a second's thought that it could harm us in any way.”

The harm done by the mobile phones is very difficult to measure mainly because phones have been massively used for a short period of time, and cancers caused by environmental factors for example, might take more than ten years to develop as Siegal Sadetzki, an israeli researcher said. “In the case of brain tumors, it may reach even 30-40 years. For example, the atomic bombs in Hiroshima and Nagasaki occurred in 1945, while the first report demonstrating brain tumors among the survivors was not published until 1994, 50 years later.”

The U.S. National Institute of Environmental Health Sciences is funding a large scale animal testing which exposes rodents to the same levels of radiation as humans are when using mobile phones, with the results being available sometime in 2013. In comparison to a number of older studies which have been inconclusive, the recent studies start to bring strong arguments supporting the fact that mobile phones can be dangerous when used for a long time.

John Bucher, a senior official at the Institute: “There have been some hints recently that there is an increase in brain cancers in people who have used these cellular communication devices for a number of years.” On the other hand, Linda Erdreich, representing the consulting company Exponent, after reviewing scientific results found no potential risk in using mobile phones. “All of the agency reports that assess the evidence using a comprehensive approach reach similar conclusions: that the current scientific evidence does not demonstrate that wireless phones cause cancer or other health effects,” she said.

Dariusz Leszczynski, one of the experts in the team formed by the subcommittee, representing Finland's Radiation and Nuclear Safety Authority said: “These studies should be aimed at proving or disproving whether human bodies respond to mobile phone radiation. In spite of years of research, we still do not have the answer to this basic question.” Some of the precautions recommended by experts might come to the aid of those that are worried about their phone's emissions: Use a wired headset instead of wireless earpieces, buy a low-radiation mobile phone, and try to keep it away from your body as much as possible.