It's no secret that cell phones emit electromagnetic radiation, but is it harmful? The CDC says there's no proof of harm. But the World Health Organization's International Agency for Research on Cancer calls the radiation "possibly carcinogenic to humans," and recent research - including an ominous 2009 Journal of Clinical Oncology study - have drawn similar conclusions.

In light of growing worries about cell phone safety, Dr. Devra Davis - the author of Disconnect: The Truth about Cell Phone Radiation, What the Industry Is Doing to Hide It, and How to Protect Your Family - says it makes sense to limit exposure to cell phone radiation. Unfortunately, she says, many cell phone users make dumb mistakes that boost their exposure. Keep clicking to see eight big ones...

Pockets and bras are a great place to keep a cell phone, right? Dr. Davis says no, pointing out that the body's absorption of cell phone signals falls off dramatically with distance. A phone held a couple of inches from the body delivers hundreds of times less radiation to the body as one held against the skin.

Why should parents discourage kids from holding cell phones against their ears? Because their skulls are thinner, for one thing, and their brains are still growing fast. Thinner skulls aren't as good at blocking cell phone radiation, Dr. Davis says. If cell phone radiation does cause damage, that means cell phones are likely to be more dangerous for kids. What does Dr. Davis think kids should do? Use a land line, text, or use the speakerphone function or an earpiece - anything to keep cell phones away from their heads.

The weaker the signal indicated on the cell phone display, the stronger the signal the cell phone puts out. And the stronger the signal, the greater the amount of radiation that's being delivered to your body. Dr. Davis says that - if possible - it's best to stick to a landline or to use the speakerphone function or use a headset when the signal is weak.

Cell phones typically emit more radiation through their backs than through the keypad side. So if you hold the phone so that its back is facing you, you may be getting an extra dose of radiation, Dr. Davis says.

Expect a conversation to run long? The longer you use a cell phone, the greater the amount of radiation that's delivered to your body - which suggests that it's best to limit cell phone calls to those take take no more than a few minutes. For longer conversations, Dr. Davis recommends using a land line.

Any negative effects from cell phone radiation are likely related to the "dose" of radiation your brain receives. To limit any possible harm to your brain, spread out the exposure by alternately holding your phone to your right side and then your left (being sure to hold it some distance away). And wait until the other party picks up before holding a cell phone close to your head to start a conversation. Cell phones put out more radiation at the beginning of each call, just as the connection is being established.

Texting is a great way to limit your exposure to cell phone radiation, so long as you don