Dial 911?

Just look around at any school or shopping mall and you'll see (and hear) one thing for sure: teens are head over ears for cell phones. By 2004, two out of three Americans between the ages of 10 and 19 will be mobile, say experts at the Boston-based research firm the Yankee Group. Yet a troubling question dogs cell phone use: do the phones possibly cause brain cancer?

Two new studies--one funded by the cell phone industry and the U.S. government, the other by the National Cancer Institute--claim probably not.

The studies compared 1,251 brain cancer patients with 1,221 cancer-free people. All subjects were short-time cell phone users who chatted less than three hours per month and owned a cell phone for three years.

Neither study proved a conclusive link between using cell phones and brain cancer. "But these studies don't answer the question, `Is it absolutely impossible for cell phones to cause brain cancer?'" says John Moulder, a cancer specialist at the Medical College of Wisconsin.

Yet not all scientists agree cell phones are harmless. Previous research has shown a possible link between cell phones and brain cancer in animals, says Louis Slesin, editor of Mircowave News. "The issue is far from settled," he says.

Cell phones emit an invisible type of energy called radio waves. When you speak into a digital cell phone, your vocal vibrations are converted into digital signals (a series of on-off pulses). The phone's antenna transmits the signals as radio waves, which bounce between radio towers and satellites in orbit above Earth.

While both sending and receiving calls, your cell phone emits a tiny amount of energy--less than one watt (energy unit per second)--next to your head. Many experts think radio waves are harmless, even at that close range. Others, like Slesin, think "the jury is still out."

Do Cell Phones Damage Your Brain?

New research suggests they don't for adults. But a team of British scientists claim that teens using mobile phones are more likely to suffer from memory loss, sleeping disorders and headaches. Why? Kids skulls are thinner than adults and more easily penetrated by radiation waves (invisible energy), which can disrupt electro-chemical brain rhythms.