Sex estimation in Filipino crania using metric and nonmetric methods.

The cranium can serve as an important indicator of sex for cases of unidentified human remains. However, the relative magnitude and expression of cranial sexual dimorphism varies across human populations such that population-specific methods are often warranted. Here, population-specific sex estimation equations are developed for both metric and nonmetric traits using contemporary Filipino crania. Cross-validated linear discriminant functions using craniometrics produced total correct classification accuracies between 78.8% and 91.3%, while logistic regression equations using cranial nonmetric traits produced total correct classification accuracies between 63.8 and 89.7%. Exogenous population equations developed in other studies are also applied to the present Filipino sample to evaluate their performance and elucidate insights on variation in human sexual dimorphism. Filipino crania generally classify extremely poorly when using either craniometric or nonmetric equations developed from other populations, with Filipino males tending to classify as female. When considering the performance of Filipinos using equations derived from other Asian groups, conventional assumptions in forensic anthropology of the homogeneity of continental ancestry groupings often do not hold up, such that one Asian population cannot automatically substitute for another Asian population without validation. This paper adds to the growing armamentarium of Filipino-specific methods for sex estimation, which may find utility in various contexts where issues of missing persons arise, including in criminal investigation, disaster victim identification, migration, armed conflict, and war dead repatriation.