But what does the report actually mean?
On "The Early Show," CBS News Medical Correspondent Dr. Jennifer Ashton said it reveals there are more unanswered questions than real answers about cell phone use. She explained the organization is just erring on the side of caution.
"They're saying. 'We just don't know, so we are going to be overly cautious,"' she said. "There could be a link. When they put this in the category of possibly carcinogenic or cancer-causing, what they're really saying is there is limited evidence existing in human beings. The animal studies also might be limited or insufficient to make a judgment, and therefore they're erring on the side of caution."
As for the possible link to brain cancer, Ashton said, cell phones basically act like a microwave, emitting potentially damaging radio frequency energy.
Recent studies, Ashton said, have shown that cell phone use can change the way brain cells use sugar or glucose, and can affect that type of metabolism with prolonged and high-frequency use.
"There can potentially be cellular changes," she said.
However, Ashton noted, when you look at brain cancer, you have to understand that the cell phone use in the world has gone up dramatically over the past decade, but brain tumor rates have really remained unchanged.
She said, "This will be an area of ongoing research."
To help avoid your exposure to the radio frequency energy emitted from the phone, Ashton said you want to keep your head as far as possible from the phone.
Ashton suggested, "You can use a hands-free device or speakerphone. ... As long as you're not driving, texting might be better, writing a letter might be better. Again, when you're inside, use a landline."
Children also may need an extra eye with their phones, Ashton said.
"When you talk about it tochildren, over three quarters of children aged 12 and under in that age group already have use of a cell phone," she said. "Again, they're using it longer, and we don't know what the effects are on the developing brain. We do know their skull is a little bit thinner than the adult skull. There are zero data looking at cell phone use in kids. Those studies will be ongoing."
CNET has prepared aon cell phone radiation, in addition to an expert Q&A on possible health risks of cellphone use and compete ratings on cellphone radiation levels.