Genotoxicity is the damage or alteration of genetic material (DNA/RNA) in the cell by biological, chemical or physical noxious agents. However, substances tested as genotoxic positive in cell or animal experiments are not necessarily carcinogenic to humans. The reason for that is, firstly, that the process of carcinogenesis is a long-term and multi-step process and secondly, data from in vitro or animal tests cannot be transmitted to humans without limitations. Additionally, humans and higher organisms also have a comprehensive DNA repair mechanism.

Genotoxic effects of electromagnetic fields are mostly investigated by the following methods: investigation of chromosome aberrations, determination of the frequency of sister chromatid exchange, comet assay and micronucleus assay.

Due to the variety of the investigated organisms and the different methods applied, the evaluation of the studies on the induction of DNA damages by radiofrequency fields is difficult. This is also reflected by the different statements of the various national and international committees.

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) comes to the conclusion in its review (p. 273) on the evaluation of the effects of radiofrequency fields that in both, in vivo and in vitro genotoxicity studies there is a general lack of effect.
The International Agency for Research on Cancer (IARC) judged that the evidence for genotoxic effects caused by radiofrequency field exposure (IARC 2013, p. 415) is weak. The IARC Working Group summarizes that approximately half of the laboratory studies of genetic damage in mammalian systems had limitations related to reporting on exposure system, small samples sizes or uncontrolled thermal effects. Of the remaining studies many were satisfactory and of comparable quality, but showed contradictory results (p. 414). The IARC Working Group also sees weaknesses in a lot of in vitro studies with regard to possible thermal effects. Results of studies where thermal effects could be ruled out mostly showed negative or contradictory data.

At European level the “Scientific Committee on Emerging and Newly Identified Health Risks” (SCENIHR) conclude that in most of the studies on genotoxicity, no effects of exposure at permissible levels were recorded, although in some cases DNA strand breaks and spindle disturbances were observed (SCENIHR, 2015, p.101 f) .
The German Committee for Radiation Protection (SSK) at the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety concludes in its statement on mobile phone-related biological effects (2011 , p. 8, in German), that the literature provides no reasonable scientifically suspicion for evidence of genotoxic effects caused by radiofrequency electromagnetic fields and the evidence for genotoxic effects is weak.
The Swiss Federal Office for the Environment (BAFU, 2014, p. 30) also sees only insufficient evidence for direct DNA damages caused by radiofrequency field exposure, although single effects were observed.

In conclusion, international and national expert committees do not see sufficient evidence for genotoxic effects caused by radiofrequency fields at permissible levels. A new statement by WHO on the effects of radiofrequency electromagnetic fields is expected in 2016.

Further information and an overview of all studies on mobile phone related exposure and genotoxicity can be found here.