WEDNESDAY, Sept. 12, 2012 —Sheryl Crow's theory is that her cellphone may have given her a brain tumor — but medical research is inconclusive.

In an interview with Katie Couric, Crow said Monday she suspects the benign brain tumor that doctors discovered in June was caused by Crow's frequent cellphone use, according to People magazine.

"There are no doctors that will confirm that. But I do have a theory that it's possible that it's related to that. I used to spend hours on the archaic old cellphones," Crow said, adding that she suspected something was wrong when she started "spacing out" on stage and forgetting song lyrics.

This doesn't mean you should hold the phone just yet. Studies have failed to show a definitive link between cellphone use and brain tumors or cancer.

The World Health Organization (WHO) started classifying cellphones as "possibly carcinogenic to humans" in 2011, placing them in the same category as some pesticides and gasoline engine exhaust.

But WHO did not classify mobile phones as definite carcinogens because many studies weren't able to confirm a direct link between cellphone use and tumors, according to Dr. Michael Schulder, vice chairman of the department of neurosurgery at Cushing Neuroscience Institute in Manhasset, N.Y.

"There was never any conclusive evidence that cellphone use causes brain tumors," he said. "The only thing going for the connection is that cellphones are little emitters of radiation like the sun, bananas, airplanes, and your TV set, but there's no evidence it can penetrate into your body to a great enough extent to cause cellular damage that can lead to a brain tumor," he said.

Since most of the studies began in the '90s, Dr.Schulder said they probably measured the impact of "archaic" phones — such as the one Crow said she once used and believed may have caused her tumor.

He also adds that Crow, who has also battled breast cancer, may have been predisposed to getting meningiomas, which are tumors that grow outside the brain but inside the skull that can cause symptoms like confusion if they compress on the brain. They are almost always benign tumors, like Crow's.

"Women at early middle age and later are most likely to get meningiomas, and there is an association between the breast cancer diagnosis and that of meningiomas," he said.

If you're worried about any harmful effects caused from your daily chats with your friends, Dr. Schulder said just use common sense. "When you're driving, you have to use a hands-free device. For prolonged conversations or frequent conversations, it's good to use something like a speaker or a wired headset," he said.