Friday, March 16, 2012

Microwaves on the brain

"Experimental Evidence that Fetal Exposure to Cell Phones Affects Behavior" runs the headline. It sounds scary enough, especially with the pregnant mother balancing a laptop above her tummy.

The report turns out to be about mice. Hmmm. Mice have a shorter gestation than humans, and therefore less time for microwaves to injure the developing brain. But they are also carried much closer to the surface. If I use sea-water as an approximation to human tissue (blood is pretty close to that) the attenuation length for microwaves in the 1GHz region is about 1.3cm. At the earliest, and most sensitive stages of human growth, the child is protected by about 7/1.3 =O(5) radiation lengths, suppressing the radiation by a factor of 200 or so, or about 50 times the protection a mouse would have at early stages.

I wish I could get at the report; I'd love to see what the significance of the effect was. The plots I can see look impressive at first glance--but why is the error bar so large at 0-exposure? Something's odd here.

I probably sound very skeptical above--and I am. But the effect isn't impossible. And we live in a sea of radio waves--the Earth is quite bright now--and even if the average effect is small, small changes in the mean cause dramatic changes in the number of people in the tails of the distribution. And here we get into territory people don't like to talk about much. Do you try to restrict cell phone use to the rich and to public safety officers, because of the risk of a few birth defects, or do you allow them because they save lives for people in trouble? (We like to think there's a perfect solution to every problem, when often there's only tradeoffs.)

No comments: