Why we can't determine reliably the age of a subject on the basis of his maturation degree

• Published in: Journal of forensic and legal medicine Vol. 61; pp. 97 - 101
• Main Authors: Milani, Silvano, Benso, Lodovico
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2019
• Subjects: Biological age; Chronological age; Forensic age; Migrant adolescents; Pathology; Biological age; Migrant adolescents; Forensic age; Chronological age
• ISSN: 1752-928X; 1878-7487; 1878-7487
• DOI: 10.1016/j.jflm.2018.12.002

Maturation is the irreversible biological process leading to adult form or function. The degree of maturation can be derived from the examination of maturity indicators, i.e. of particular aspects of the overall maturation, such as pubertal status, skeletal and dental morphology. Rhythm of maturation of each indicator differs between populations and individuals, because of genetic, nutritional and environmental factors. Skeletal maturation is usually expressed as skeletal age, which is the median age at which a given degree of maturation is attained. Despite its name, skeletal age indicates a degree of maturation and not a chronological age. This misinterpretation still results in a confused, unprofitable, and endless debate about the reliability of forensic age and its ethical, deontological, legal and scientific aspects, while its estimation is gaining raising importance in forensic practice, due to increasing migration movements towards Europe. This paper clarifies the meaning of biological age compared to chronological age, quantifies the uncertainty associated with forensic age in terms of biological variability (differences in the degree of maturation of subjects with the same chronological age), bias (systematic differences between ethnic groups), and lack of precision (random errors made in the evaluation of an X-ray image). Because of the inter-individual variability, the interval between the 3rd and 97th centile of chronological age distribution of healthy adolescents sharing the same skeletal age and belonging to a given population has width of at least ±2 years about the skeletal age (uncertainty interval). This – and not others – uncertainty interval (±2 years) is the only interval that should be specified by the expert witness, when he presents his estimate of the age of an adolescent without identification documents. Expert witnesses should be aware that the age of an adolescent can be determined only with rough approximation, even when they assess maturation with the most reliable method, and that, when they produce their conclusions to the judicial or public security authorities who requested to determine the age of an adolescent, they are determining for ever the fate of a young human being. •The concepts of maturation and biological age are critically reviewed.•Biological maturation is used to estimate the age of adolescents of unknown age.•Biological age is a measure of degree of maturation, not of chronological age.•The reliability of the estimate crucially depends on biological variability.•Due to this, the uncertainty interval of the estimate cannot be lower than ±2 years.