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 (M1 ) to determine sex in adult and immature individuals within and between populations.

METHODS: Ten M1 dimensions were measured in 91 adults (19-55 years) and 58 immatures (5-18 years) 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.

RESULTS: 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.

CONCLUSIONS: This 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.