Most would argue that cell phones have changed our lives for the better. They have enhanced  personal security, quickened emergency response and given us the ease of instant communication. But the radiation they emit could be placing us at risk for cancerous brain tumors. 

They are the symbols of our time. 

Cell phones.  From Europe, to Asia to the Middle East, four billion people use them worldwide.

In this Chinese film, aptly titled "Cell Phone," a man's life is destroyed by his cell phone when he forgets it at home.  His wife discovers it and his affair with a younger woman.
A Senate Hearing this week didn't deal with people's private lives.

International researchers and U.S. lawmakers looked at whether radiation emitted from cell phones will kill you.

They did agree that some studies have linked heavy, long-term cell phone use to cancer of the brain.

Physician Siegal Sadetzki advises Israel's Health Ministry.

"I believe that cellphone technology which has many advantages is here to stay," Sadetzki said. "The  question that needs to be answered is not whether we should use cell phones but how we should use them."

Health warnings to cell phone users have been issued by governments of several countries.

Dr. Linda Erdreich represents the $4 trillion wireless industry. She says there's no need for concern.

"The current evidence does not demonstrate that phones cause cancer or other adverse health effects," Dr. Erdreich said.

But Teresa Gregorio's experience raises questions.  She says she used a cell phone, beginning in the mid-1990's, even giving up her land line.  Bad news came in 2008. She has an inoperable brain tumor.

"I had used a cell phone for 2-3 hours a day right here on my right side, right where my tumor was or is," she explained.

270 million people in America use cell phones. Seventy percent of teens or pre-teens have them.  Younger children are even more vulnerable.

"Radiation gets much more deeply into the head of a 5-year-old or a 3-year-old than it does into that of an adult," Epidemiologist Devra Lee Davis explained. 

She says children, because they have thinner skulls, are more at risk. "The science needs more work," she said, "but I want to ask are we really prepared to risk our children's brains until we find out for sure whether this is a hazard?"

Although results of studies on a cancer link are contradictory, scientists are urging consumers to be safe rather than sorry. 

The idea is to keep the phone away from the body.  Use earphones or a headset, keep your phone on your belt-- not in your pocket.

Texting is better. It keeps the radiation down and the phone further away from you.

Senator Tom Harkin chaired the hearing. He says he's just beginning to ask questions.

"I am reminded of this nation's experience with cigarettes.  Decades passed between the first warnings about smoking tobacco and the final definitive conclusion that cigarettes cause lung cancer," Harkin said.