http://www.reuters.com/newsArticle.jhtml?type=technologyNews&storyID=7141544
"Radio waves from mobile phones harm body cells and damage DNA in laboratory conditions, according to a new study majority-funded by the European Union, researchers said on Monday."
"After being exposed to electromagnetic fields that are typical for mobile phones, the cells showed a significant increase in single and double-strand DNA breaks. The damage could not always be repaired by the cell."

Until a plausible physical explanation for how centimeter-wavelength radiation can concentrate the energy required to break up the chemical bonds in micrometer-scale DNA molecules, I will remain skeptical of this.

The phsyical process behind cell damage from ionizing, gamma, x-ray or neutron radiation is easily understood, as is chemical damage to DNA structure. However, there is no known physical process whereby such relatively long-wavelength energy as microwaves could influence individual molecules, even as large ones as DNA.