Using cell phones has not been proven (yet?) to result in increase in the risk of cancer. A team of Swedish scientists recently published results of a case–control study on brain tumor cases of men and women aged 18–75 years and diagnosed during 2007–2009. In total 709 meningioma (the most common benign brain tumor accounting for about 30% of brain tumors) cases and 1,368 control subjects answered the questionnaire. Mobile (basically, any cordless) phone use did not prove to have any statistically significant impact on the risk of getting the tumor.
We try to use land-line phones whenever possible, but do not feel guilty when talk by cell phones. Moreover, it seems safer to use your personal cell phone than a public land-line telephone due to a great deal of germs one can catch.