Children and adolescents are more exposed to RF-EMF than adults due to thinner skull bone, higher conductivity in the brain tissue, and a smaller head. Also the developing brain is more vulnerable than in adults and it is still developing until about 20 years of age [31]. We analysed glioma risk in different age groups for first use of a wireless phone. Regarding both mobile and cordless phones OR was highest among sub-jects with first use before 20 years of age. The risk increased further for ipsilateral use to OR = 2.3, 95% CI = 1.3–4.2 for mobile phone use and to OR = 3.1, 95% CI = 1.6–6.3 for cord-less phone use. These results are consistent with our previous findings [8,15,29,30].