My new cell phone has a speakerphone. That's nice, because it means I don't need to put the little device (which just happens to emit microwave radiation) next to my head. According to this article:

Their previous studies proved radiation could open the blood-brain barrier, allowing a protein called albumin to pass into the brain. Their latest work goes a step further, by showing the process is linked to serious brain damage. Professor Salford said the long-term effects were not proven, and that it was possible the neurons would repair themselves in time. But, he said, neurons that would normally not become "senile" until people reached their 60s may now do so when they were in their 30s.