Background: Age estimation of a minor whose identity is unknown must be accurate enough to respond to judicial requests. The main objective of this study is to accurately determine a teenager's age from simple and reproducible criteria. Samples and methods: The first reference sample consists of 1720 measurements collected from 170 teenagers aged 11 to 16, over a period of five years. A second validation sample of 735 teenage boys aged 11 to 16 made it possible to verify the relevance of our estimates. The degree of maturation was determined using 4 pubertal stages: the stage below the age of puberty; the pre-pubescent stage; the para-pubescent stage and the pubescent stage. For each pubertal stage an optimization of the values of the age was carried out in order to reduce the differences between the estimated and the actual age at the different age groups. Results: The mean differences between estimated age and actual age from this values was-0.06 ± 0.91 years for the reference group and-0.49 ± 0.73 years for validation group. Conclusions: Our method of age estimation is simpler and accurate. It could be used routinely in a forensic frame to respond to judicial requests.