||The purpose of this opinion is to update the SCENIHR opinion of March 2007 in the light of newly available information, and to provide a methodological framework and corresponding guidelines to evaluate available scientific evidence in order to ensure the best possible quality for risk assessment. In order to update the opinion, a scientific rationale was established. This rationale contains relevant scientific knowledge from the physical, engineering, medical and biological sciences which is critically evaluated and summarised. When appropriate, gaps in knowledge are highlighted and suggestions for future important areas of research are included. This opinion also addresses the issue of childrens sensitivity, and in particular dosimetry aspects of radiofrequency exposure of children.