A new multivariate method for determining sex of immature human remains using the maxillary first molar

Objectives This study investigated the use of sexually dimorphic metrics of the first permanent maxillary molar (M-1) to determine sex in adult and immature individuals within and between populations. MethodsResultsTen M-1 dimensions were measured in 91 adults (19-55years) and 58 immatures (5-18years) from two English populations, one of documented sex (Spitalfields crypt) and another of morphologically-assigned sex (Black Gate). Preliminary statistical analysis was undertaken to explore bilateral differences and variation by age and sex, followed by multivariate analyses to predict sex from dental metrics. Both cross-validated linear discriminant analysis and binary logistic regression predicted biological sex consistent with known sex in 94.6% of adults and 90.9% of immatures. When functions extracted from the Spitalfields data were used to assign sex to Black Gate adults, consistency with morphological sex varied from 83.3% to 57.7%. A new function developed on Black Gate resulted in only a 4.8% increase in maximum accuracy but reduced bias. The immature cohort comprised 19 (52.8%) males and 17 (47.2%) females. ConclusionsThis study demonstrates substantial sexual dimorphism in a single tooth which is commonly preserved in archaeological and forensic contexts. It successfully assigns biological sex to immatures from 5 years of age with substantially greater accuracy than any other morphological or metric method. We suggest that accurate cross-population functions based on dentition require a trade-off between accuracy and applicability, and that functions extracted from populations of documented sex can be used to assign sex to other archaeological and forensic remains.