Sex Estimation Methods Research Articles

Sex estimation of teeth at different developmental stages using dimorphic enamel peptide analysis.

This study tests, for the first time, the applicability of a new method of sex estimation utilizing enamel peptides on a sample of deciduous and permanent teeth at different stages of mineralization, from nonadults of unknown sex, including perinates. A total of 43 teeth from 29 nonadult individuals aged from 40 gestational weeks to 19 years old were analyzed. The sample included pairs of fully mineralized and just developing teeth from the same individual. The individuals were from four archaeological sites in England: Piddington (1st-2nd centuries AD), Coach Lane, Victoria Gate, and Fewston (all 18th-19th centuries). A method that identifies sex chromosome-linked isoforms of the peptide amelogenin from human tooth enamel was applied. The method utilizes a minimally destructive acid etching procedure and subsequent nano liquid chromatography tandem mass spectrometry. It was possible to determine the sex of 28 of the nonadult individuals sampled (males = 20, females = 8, undetermined = 1). Only one sample failed (CL9), due to insufficient mineralization of the sampled tooth enamel. Data are available via ProteomeXchange with identifier PXD021683. Sufficient peptide material to determine sex can be recovered even from the crowns of developing perinatal teeth that are not fully mineralized. The minimally destructive and inexpensive (compared to ancient DNA) nature of this procedure has significant implications for bioarchaeological studies of infancy and childhood.

Coronal and sagittal suture lengths as novel measurements for sex identification in a sample from the Egyptian population.

Sex estimation from isolated or fragmented bones is a cornerstone in medicolegal identification. The current study aimed to estimate sex from the lengths of the coronal and sagittal sutures in a sample of Egyptians. The study was performed on a total of 80 adult cadavers (48 males and 32 females) during a routine autopsy. After exposure of the skull vault, the lengths of the coronal and sagittal sutures were measured using a thread and a graduated scale. The mean length of the coronal suture was significantly higher in males (24.8 ± 1.4 cm) than in females (22.7 ± 1.4 cm). The mean length of the sagittal suture was significantly higher in males (11.9±1.6 cm) than in females (10.8±1.6 cm). This study used the lengths of the coronal and sagittal sutures as measurements for sex estimation for the first time. Receiver operator characteristic (ROC) curve analysis revealed that the combined coronal and sagittal sutures lengths were the best sex discriminator (AUC= 0.859), followed by the coronal suture length (AUC= 0.855), and sagittal suture length (AUC= 0.697). Moreover, regression analysis was performed for sex determination; the highest accuracy was obtained by an equation that included the lengths of the coronal and sagittal sutures together (76%); followed by the coronal suture length (75%); then the sagittal suture length (71%). These measurements are easily obtained during a conventional autopsy and this method of sex estimation is cost effective when compared to radiological and DNA analysis. Moreover, the measurements can be carried out on dry skulls as long as the vault has identifiable landmarks.

Advancements in sex estimation using the diaphyseal cross-sectional geometric properties of the lower and upper limbs.

This paper introduces an automated method for estimating sex from the lower and upper limbs based on diaphyseal CSG properties. The proposed method was developed and evaluated using 389 femurs, 412 tibias, and 404 humeri of adult individuals from a modern Greek reference sample, the Athens Collection. The skeletal properties, which were extracted with the CSG-Toolkit, were analyzed with step-wise DFA (evaluated with LOOCV) and subsequently with RBF kernel SVM supervised learning. SVM cross-validation was based on a 20-fold stratified random sample splitting as well as a chronological split based on year of birth to further assess the effect of secular change in sex estimation capacity. Maximum cross-validated classification accuracy from step-wise DFA reached 94.8% for the femur, 94.7% for the tibia, and 97.3% for the humerus, whereas SVM cross-validated results were similar although slightly lower, mainly due to the more strict cross-validation scheme. Our results suggest that the proposed sex estimation method is reasonably robust to secular change, since there was limited loss in classification accuracy between different chronological groups, despite the presence of secular change in stature of the Greek population during the examined period. The proposed method has been implemented as a function for the GNU Octave environment, named estimate_sex, which comprises a self-intuitive graphical user interface for facilitating sex estimation and is freely available under a suitable license.

Test of the auricular surface sex estimation method in fetuses and non-adults under 5years old from the Lisbon and Granada Reference Collections.

Non-adult sex estimation is an active field of forensic inquiry as morphological variations between males and females are subtle, but observable, even from intrauterine development. The objectives of this study are threefold: to test the validity of the auricular surface method for sex estimation (Int J Osteoarchaeol 27:898-911, 2017) in fetuses and children under the age of 5years old; to evaluate if health conditions, reported as the cause of death, influence its accuracy; and to detect possible secular trends in sexual dimorphism. One-hundred and ninety-seven skeletal individuals from the Lisbon and Granada Identified Collections were studied. Individuals were divided according to the hormonal peaks (< 0, 0-2, < 2, and 2.1-5years old), cause, and year of death (before and after 1960). As in previous studies, two ratios (FI/CF and DE/AD) and two qualitative variables (OM and MRS) showed the highest frequencies of correct estimation (0.81-0.86). The correct sex allocations increased when the discriminant function (0.85) and logistic regression (0.86) were applied. Males of the age groups < 0 and 2.1-5years were all correctly sexed by both formulae, and the same was observed for the female probabilities of adequate allocation. The cause and year of death were identified as variables without statistical significance. It is proposed that this method can be incorporated with confidence into the multifactorial laboratory protocols for non-adult sex estimation from skeletal remains.

Evaluation of the auricular surface method for subadult sex estimation on Italian modern (19th to 20th century) identified skeletal collections.

Sex estimation in subadult skeletal remains is still considered highly problematic. The aim of this research is to test the reliability of the method of subadult sex assessment proposed by Luna and co-workers in 2017, based on the analysis of the auricular surface of the ilium. Seven ratios and three morphological traits were recorded for 127 subadult individuals (63 males and 64 females), aged between 0 and 17 years, from several Identified Skeletal Collections of the University of Bologna. Nonparametric Mann Whitney test, Kolmogorov Smirnov test, and the Pearson correlation coefficient were used for continuous variables, whereas the Cramer Coefficient was calculated for qualitative variable. A principal component analysis was also performed on ratio values. The statistic ƞ was taken into account for both types of variables. None of the ratios presented significant dimorphic results. Two qualitative variables show statistically significant differences between sexes. The overall morphology proved to be an accurate sex predictor among children aged ≥4 years (78%-86%) and meets the minimum accuracy standard (75%) for subadult sex estimation for individuals between 1 and 17 years of age. The morphology of the retroauricular end of the superior demiface (MRS) can be used with a high level of accuracy for sexing individuals from 1 to 12 years (77%-81%). The metric variables did not replicate the accuracy values originally obtained by Luna and co-workers. Otherwise, the evaluation of the morphological variables proposed by the authors yielded promising results as a reliable sexing technique for individuals who died before puberty.

Sex estimation by odontometrics of nonadult human remains from a contemporary Italian sample

The objective was to develop an odontometric technique for sex estimation based on dental measurements from adult individuals, and to evaluate its applicability and reliability for diagnosis of sex of nonadult skeletal remains. This study was conducted on the permanent dentition of 132 individuals (70 males, 62 females) from the identified human skeletal collection of the Certosa Cemetery (Bologna, Italy) of the University of Bologna. Binary logistic regression equations were developed based on dental measurements of the permanent teeth of the adult individuals, and these equations were subsequently applied to the permanent dentition of nonadult individuals to estimate their sex. These data show that the canine teeth of both the maxilla and mandible are the most sexually dimorphic teeth in adults, followed by the mandibular second molar, maxillary and mandibular second and first premolars, and mandibular first molar. These data provided correct assignment of sex in 80.4-94.9% of cases, which depended on the measurements used. Of the 26 nonadult individuals of the experimental sample, sex diagnosis was possible for 22, which represented an applicability rate of 84.6% of the individuals. Comparing the sex of these 22 nonadult individuals estimated by odontometrics with the known biological sex, correct assignment was obtained in 90.9% of cases. As a method of sex estimation, odontometric analysis of permanent dentition can be used successfully for nonadult human skeletal remains in both forensic and archeological contexts.

Development of a sex estimation method for skulls using machine learning on three-dimensional shapes of skulls and skull parts

• A sex estimation method for skulls using machine learning was developed. • Homologous three-dimensional skull shapes with 40,962 vertices were modeled. • Partial least squares regression (PLS) was applied to dimensionality reduction. • Support vector machine (SVM) effectively classified the sex using PLS components. • Greater reliability is expected by increasing the training data for the SVM. Sex estimation from the skull plays an important role in the identification of skeletal remains. A novel sex estimation method from three-dimensional shapes of the skull using machine learning technology is presented. A total of 100 skull shapes were obtained from post-mortem computed tomography data. Homologous models of the whole skull, the cranium only, and the mandible only were created and the coordinates of 40,962 vertices of the models were reduced in dimensionality by principal component analysis (PCA) and partial least squares regression (PLS). Known sexes and the scores of the obtained components were supplied to the support vector machine, and the accuracy rates of sex estimation were obtained by a 10-fold double-looped cross-validation procedure., Lastly, the developed method was applied to six casework skulls with known sexes to validate the power of the estimation. By reducing dimensionality with PLS, remarkably high accuracy rates were obtained in the estimation. The rates reached 100% in all parts examined, while the rates of parts reduced with PCA remained around 90%. Virtual shapes created from very large and small scores of the first and second components of PLS showed the clear sexual dimorphisms that have been proposed by many researchers. The validation results on actual casework skulls were less acceptable than expected, suggesting the necessity of further study with greater numbers of samples for machine learning. The sex estimation method developed here enables us to perform objective identification of skeletal remains required in forensic anthropology field.

A comparison of proteomic, genomic, and osteological methods of archaeological sex estimation

Sex estimation of skeletons is fundamental to many archaeological studies. Currently, three approaches are available to estimate sex–osteology, genomics, or proteomics, but little is known about the relative reliability of these methods in applied settings. We present matching osteological, shotgun-genomic, and proteomic data to estimate the sex of 55 individuals, each with an independent radiocarbon date between 2,440 and 100 cal BP, from two ancestral Ohlone sites in Central California. Sex estimation was possible in 100% of this burial sample using proteomics, in 91% using genomics, and in 51% using osteology. Agreement between the methods was high, however conflicts did occur. Genomic sex estimates were 100% consistent with proteomic and osteological estimates when DNA reads were above 100,000 total sequences. However, more than half the samples had DNA read numbers below this threshold, producing high rates of conflict with osteological and proteomic data where nine out of twenty conditional DNA sex estimates conflicted with proteomics. While the DNA signal decreased by an order of magnitude in the older burial samples, there was no decrease in proteomic signal. We conclude that proteomics provides an important complement to osteological and shotgun-genomic sex estimation.

Experimental assessment of the surface quality of 3D printed bones

ABSTRACT 3D printed replicas of human remains are useful tools in courtroom demonstrations. Presently, little published research has investigated the surface quality of printed replicas for use in the presentation of forensic anthropology evidence. In this study, 3D printed replicas of nine human bones were reconstructed from computed tomography (CT) scan data using selective laser sintering (SLS). A three-phased approach assessed: i) the metric accuracy of the 3D prints; ii) the viability of applying age and sex estimation methods (with multiple observers (n = 8); and, iii) the surface quality using a customized scoring method (with multiple observers (n = 8)). The results confirmed that the prints in this study were accurate to within 2.0 mm of the original dry bone. Observers were able to confidently assess the gross features of the prints; however fine surface details were not always well represented compared to the dry bones. These findings confirm the applicability of 3D printed replicas for courtroom exhibition of gross features but offer caution against their use when fine detailing is important for evaluative interpretation.

Micro-CT analysis of the internal acoustic meatus angles as a method of sex estimation in skeletal remains.

The aim of the present study was to verify the lateral angle method for sex estimation by using computed micro-tomography. Two measurements of the anterior lateral angle of the internal acoustic meatus were assessed. The performed analysis revealed that the mean angle at the level of transverse crest of the fundus of the internal acoustic meatus in adults is significantly greater in females (45.58° vs. 39.68°; p < 0.05). A 45° sectioning point was applied, and sex allocation using this measurement was correct in 81.81% of adult samples. In turn, when utilizing the measurement at the level of modiolus of the cochlea, we did not obtain a satisfactory result in sex classification (59.09%). In subadults (male and female samples), the anterior lateral angles were undifferentiated. Thus, the conducted micro-CT analysis shows that the anterior lateral angle measurement method can be used as a preliminary indication of sex in adult individuals.

Sex estimation of skeletons in middle and late adulthood: reliability of pelvic morphological traits and long bone metrics on an Italian skeletal collection.

There are several metric and morphological methods available for sex estimation of skeletal remains, but their reliability and applicability depend on the sexual dimorphism of the remains as well as on the availability of preserved bones. Some studies showed that age-related changes on bones can cause misclassification of sex. The purpose of this study was to establish the reliability of pelvic morphological traits and metric methods of sex estimation on relatively old individuals from a modern Italian skeletal collection. The data for this study were obtained from 164 individuals of the Milano CAL skeletal collection and average age of the samples was 75years. In the pelvic morphological method, the recalibrated regression formula of Klales and colleagues (2012), pre-auricular sulcus, and greater sciatic notch morphology were used for sex estimation. With regard to the metric method, 15 standard measurements from upper and lower limbs were analyzed for sexual dimorphism. The results showed that in pelvic morphological approach, the application of regression formula of the revised Klales and colleague formula (2017) resulted in 100% accuracy. Classification rates of metric methods vary from 75.19 to 90.73% with the maximum epiphyseal breadth of proximal tibia representing the most discriminant parameter. This study confirms that the effect of age on sex estimation methods is not substantial, and both metric and morphological methods of sex estimation can be reliably applied to individuals of Italian descent in middle and late adulthood.

Validating the probabilistic sex diagnosis (DSP) method with a special test case on Pre-Columbian mummies (including the famous Rascar Capac)

Many museums have either one or more mummies in their collections. The Royal Museums of Art and History in Brussels is no exception and houses several Pre-Columbian mummies, including the one that inspired Hergé, author of the Tintin comics, to create the character of ‘Rascar Capac’. The accurate identification of the sex of a particular mummy is important for testing hypotheses about social structures in ancient societies. Sexing of mummies is mostly based on visual analysis from CT and MRI scans and macroscopic examination from the skeletal tissue such as genitalia and breasts, although skeletal tissue is not always well preserved.Probabilistic Sex Diagnosis (DSP: Diagnose Sexuelle Probabiliste) is a sex estimation method which has recently proved to be highly effective on different modern human and ancient European populations. The aim of this study was to see if it was possible to apply and validate virtual DSP on a study of four ancient Pre-Columbian mummies from South America (which are outside the reference population of DSP).Virtual DSP was performed in the software ‘lhpFusionBox’. All mummies were CT scanned, 3D models were created and virtual DSP was performed. Sex was determined with a probability of 99.9% or over in all cases (DSP determined one male and three females). Preserved skeletal tissue remains confirmed DSP results in half of the mummies. A Principal Components Analysis (PCA) was performed on the DSP results of the mummies and a modern human (MH) population. Half of the mummies were outside the 95% range of the DSP values of MH, largely due to their smaller size. When size was accounted for, they were within the MH range. The unknown sex mummies identified as females by DSP were found to be grouped with the known sex female mummy and the MH females. Similarly, the unknown sex mummy identified as male by DSP was also found to be grouped with MH males.The use of PCA analysis on DSP results is an effective tool to validate DSP results, even with individuals outside of the reference population. Despite differences in size from ancient to modern humans, DSP was found to be accurate and can be used with mummies and other ancient populations from different countries around the world.

Estimating sex from the seven cervical vertebrae: An analysis of two European skeletal populations

Methods for estimating sex from a variety of skeletal elements is vital in forensic anthropology as many of the traditionally studied bones are often fragmented upon recovery. The current study examined the seven cervical vertebrae to establish an accurate sex estimation method for Europeans. Discriminant functions were developed from the seven cervical vertebrae using the maximum body height (CHT), vertebral foramen anterior-posterior diameter (CAP), and vertebral foramen transverse diameter (CTR). To date, no study has used these variables to estimate sex from human remains. Two hundred and ninety-five adult individuals (157 males, 138 females) from the University of Athens and the Luis Lopes skeletal collections were studied. No population differences were exhibited between the contemporary Greek and historic Portuguese skeletons, indicating that discriminant functions for sex estimation from the cervical vertebrae may not be population- or temporally-specific. The results of this study indicate that only CHT and CTR exhibited statistically significant sexual dimorphism. Seven multivariate discriminant functions were developed with accuracy rates between 80.3% and 84.5%. Cross-validation studies showed that five of the seven functions exhibited strong statistical algorithms. This study will assist with estimating the sex of unknown Europeans from the cervical vertebrae especially in cases where more accurate predictors of sex, such as the skull or the pelvis, are unavailable.

An Analysis of Hounsfield Unit Values and Volumetrics from Computerized Tomography of the Proximal Femur for Sex and Age Estimation.

Sex and age are two elements in the establishment of a biological profile for forensic identification. While the pelvic bones are the most ideal structures for sex estimation, the condition of a body is not always ideal due to the nature of death, such as in mass disasters, or postmortem processes. This study utilized CT scans and resultant 3D models of 100 male and 100 female adults of known ages ranging from 18 to 98years old to collect volumetric and Hounsfield unit measurements of the proximal femur. Equations were created to establish logistic regression models for sex estimation and linear regression models for age estimation. The resultant sex estimation method had an accuracy of 93.5% and utilized the volume of the proximal femur. This study provides three linear regression models for age with an accuracy range of 86%-92% ±12years. As imaging technologies are increasingly adopted for forensic purposes, the power of 3D data will provide the opportunity for more quantitative and reproducible analyses. The proposed method for sex and age estimation provides a reliable tool that can be utilized in both day-to-day casework and disaster victim identification.

Distal Humerus Morphological Variation and Sex Estimation in Modern Thai Individuals.

Due to differential preservation, it is necessary to develop sex estimation methods on varied anatomical regions, including the distal humerus. Sexually dimorphic differences of the medial epicondyle angle, olecranon fossa shape, trochlear extension, and trochlear constriction have been documented in several non-Asian groups. This study examines distal humerus morphological variation in 616 modern Thai individuals (f=198; m=418) 18-96years old and tests the methods on a hold-out sample of 152 individuals (f=91; m=61). The results indicate that population-specific binary probit regression performs the best (74.1-100%), followed by composite scoring (77.0-90.1%), binary logistic regression (63.3-92.2%), and univariate sectioning points (37.7-90.1%). Age minimally effects the expression of the medial epicondyle angle in males, and trait scoring is susceptible to high intra- and interobserver error. While demonstrating relatively high sex biases, distal humerus morphology can be used to estimate the sex of Thai individuals when more sexually dimorphic regions are absent.

Sexual dimorphism in the cervical vertebrae and its potential for sex estimation of human skeletal remains in a white scottish population

BackgroundBiological sex determination from skeletal human remains is crucial in archaeological and forensic settings. The purpose of the current study was to evaluate the presence of sexual dimorphism in seven (C1C7) cervical vertebrae dimensions and to further establish a reliable sex estimation method using C1C7 for a White Scottish population. MethodIn this study, three morphometric characteristics from the cervical vertebrae were measured; maximum vertebral body height (CHT), maximum anterior-posterior diameter of vertebral foramen (CAP) and maximum transverse diameter of vertebral foramen (CTR). One-hundred and fifty (150) cervical vertebrae from a total of twenty-five (25) human cadavers (13 males, 12 females) ranging in ages 49 to 103 years were studied. ResultsThe resulting statistical analysis showed that CHT measurements exhibited the greatest degree of sexual dimorphism at all cervical vertebral level followed by CTR measurements. CAP measurement only exhibited significant sexual dimorphism at the second cervical vertebra (C2AP). A total of 25 multivariate discriminant functions were generated that were statistically significant and successfully assigned sex with an 81.8%–100% accuracy range. A cross-validation study was also performed to establish the reliability of the 25 functions and only eight out of 25 functions exhibited weak statistical reliability. ConclusionStatistically significant sexual dimorphism in the cervical vertebral dimensions (CHT and CTR) was conclusively established with the second cervical vertebrae (C2) exhibiting the greatest sexual variance in the cervical vertebral column of a White Scottish population. Age-related changes were not observed in the vertebral dimensions of the study sample and this may however be due to the insufficient sample size for each age category.

Estimating sex using isolated appendicular skeletal elements from Chachapoyas, Peru

AbstractThe estimation of sex from human skeletal remains is one of the primary steps in the creation of a bioarchaeological demography. Conventionally, sex has been estimated from the crania or os coxae, but commingled contexts pose challenges when associating these key elements with the rest of the remains becomes impossible or if the sample is mostly represented by postcranial appendicular elements. Following successful applications of logistic regression to appendicular metrics in forensic anthropology for the estimation of sex using appropriate reference samples, this study aims to create a similar method to be applied in archaeological contexts in the Andes. This is achieved through the collection of osteometric data from complete burials of previously estimated sex recovered at the archaeological site of Kuelap, in Chachapoyas, Peru. Using these data, we created logistic regression formulae, using both frequentists and Bayesian approaches, that utilize standard metrics of the humerus, femur, and tibia to estimate the sex of individuals in this sample, testing their apparent accuracy and, through their application to a commingled context, their applicability in situations when only appendicular remains may be present or complete. Both frequentist and Bayesian‐derived formulae provided a correct classification of between 82% and 93% for the previously estimated sample, on par with correct classification rates of cranial nonmetrics. No significant difference was observed between the Bayesian approach and the frequentist approach. The application of this method for sex estimation to a commingled context also provided a demography consistent with that created using only os coxae and cranial remains. These results underscore the validity and reliability of this methodology and provide further support for its application in other bioarchaeological contexts across the Andean region.

CADOES: An interactive machine-learning approach for sex estimation with the pelvis

The pelvis is consistently regarded as the most sexually dimorphic region of the human skeleton, and methods for sex estimation with the pelvic bones are usually very accurate. In this investigation, population-specific osteometric models for the assessment of sex with the pelvis were designed using a dataset provided by J.A. Serra (1938) that included 256 individuals (131 females and 125 males) from the Coimbra Identified Skeletal Collection and 38 metric variables. The models for sex estimation were operationalized through an online application and decision support system, CADOES. Different classification algorithms generated high accuracy models, ranging from 85% to 92%, with only three variables; and from 85.33% to 97.33%, with all 38 variables. CADOES conveys a probabilistic prediction of skeletal sex, as well as a suite of attributes with educational applicability in the fields of human skeletal anatomy and statistics. This study upholds the value of the pelvis for the estimation of skeletal sex and provides models for that can be applied with high accuracy and low bias.

Determinations of Cranial Dimorphism in Sagittal Section in CT Scans

The objective of this study was to analyze if the linear measurements performed on 206 CT scans are dimorphic and can be used as an auxiliary method for forensic identification as a secondary method according to INTERPOL 2014. A logistic regression model was developed to determine the sex of the individual analyzed. The measurements were performed on computed tomography of the Osteological Biobank and tomography of FOP_UNICAMP, in 117 male and 89 female CT scans with known age, ancestry and cause of death. OnDemand3D® software was used for the following measures: sella turcica (center) to nasal suture, sella turcica (center) to anterior nasal spine, sella turcica to ENP, sella turcica (center) to start; Nasal suture to ENA; Nasal suture to the ENP, in the median sagittal section. The Kolmogorov-Smirnov test was used to establish the distribution and equality of variances (homoscedasticity) of the variables under study. The unpaired t-test and the Pearson correlation coefficient were conducted, resulting in a logistic regression using the Stepwise-Forward method for sex. This study was approved by CAAE 54171916.0.0000.5418. It was verified that all measures studied are dimorphic, but the ß of the measures PPST-ENA; SNRE-ENA; SNRE-ENP; ENA-ENP were the most statistically significant, being selected to determine the multiple model. The logistic regression model was created: [Logit: -19.909 + 0.177 (SNRE-ENA) + 0.231 (ENA-P)]. The model obtained in this study, presented a 77.2% accuracy, being a good result to be used as a coadjuvant method to other sex estimation methods in mixed populations, such as Brazil.

Sex estimation of femur using simulated metapopulation database: A preliminary investigation

Accurate and reliable methods of sex estimation are essential in forensic practice. In the literature, both the population based and non-population specific standards are existing. In the present work, the summary statistics of 3 femoral standard measurements (joints and length diameters) were collected from 13 published studies of modern populations. The metric data of each population were regenerated using truncated normal distribution approach. A simulated metapopulation database was constructed using the combined metric data of 2275 femur bones. Despite interpopulation differences, the calculation of stable non-population specific discriminant functions (DF) was possible using the most discriminatory variables selected by stepwise analysis.The functions were tested on raw data of 6 populations which were obtained from authentic sources. The pooled DFs produced lower but comparable accuracies to the population specific functions using fewer number of variables. The total allocation accuracies of the temporally distant Terry collection did reach better than 90% in both American whites and blacks while in the contemporary Turkish and Hispanic samples were more than 85%. In Asian populations, the total accuracies ranged from 69.7% to 84.9%. Nevertheless, raising the posterior probability threshold to 0.95 increased the total allocation accuracies above 95% in all populations using the pooled populations function of femur joints diameters. This function permitted the classification of one third to more than half of the total sample size in each population which suggest a considerable practical value in estimating sex of unknown individuals without a priori recognition of population affinity.