Drivers who use hands-free cellular devices while driving may be doing themselves a favor in the long run. That’s because scientists still can’t say with certainty that placing a cell phone against the head is completely safe, especially for heavy users and people who began using the devices as children. They point to lingering questions over the potential health effects from the energy emitted by the phones, specifically the long-debated risk of developing brain cancer.
“It’s fair to say that the data aren’t all in yet,” says Dr. David L. McCormick, a biologist and director of the Illinois Institute of Technology Research Institute in Chicago, who has studied the issue. “There are a small number of epidemiological studies that have suggested a possible increase in cancer risk. But comparable studies in other populations haven’t confirmed these findings.”
To know how far the effect, I think you can read the full article from this link
(by Shari Roan | Los Angeles Times...)