Information about the laterality of cell phone use is a key parameter in epidemiologic studies investigating the association between exposure to RF-EMF emitted from cell phones and the risk of developing a brain tumor. Here, possible reporting biases could have tremendous influence on the risk estimates. Until now no research is available that might help to evaluate this possible bias. People with a brain tumor might tend to over-report the use of cell phones on the side of the head where their tumors are located. The proposed study tries to assess the reporting bias with respect to the laterality of cell phone use in a simulation experiment.