As you read this story, is your cell phone in your pocket or purse, on your desk beside you, or even in your hand? On a planet of 6.8 billion people, about 5 billion use cell phones. But could radiation from those phones be harmful to your health? In her new book, Disconnect: The Truth About Cell Phone Radiation, What the Industry Has Done to Hide It, and How to Protect Your Family, Devra Davis, an environmental health scientist formerly with the National Academy of Sciences, says the answer is a resounding yes. Over the years, scientists and public health officials have explored the effects of mobile phone radiation on human health. Time and again, they've said that while more research is needed to examine potential long-term effects, fears of cell phones are mostly unfounded. But Davis, who says she was once a skeptic herself, argues that compelling evidence to the contrary exists in research institutions around the world. Disconnect resurrects decades-old studies on the topic and probes new research to build a case for why cell phone radiation is now a "national emergency." "What I'm really concerned about here and why I wrote this book is because there's a lot of really compelling experimental evidence on the effect of electromagnetic fields on cells. We are already seeing a doubled risk of brain cancer in people who have used cell phones heavily for 10 years in the few studies that have been done," [said Davis].