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.