In the NamUs system, biological sex and sex assigned at birth refers to the classification of individuals as male or female based on genetic characteristics at birth. This classification is essential for forensic and investigative purposes, as it helps with case searching, case cross-matching, and scientific analysis, including DNA comparisons and anthropological assessments. We recognize that some cases may not fit strictly within these categories due to medical and genetic conditions (i.e. individuals who have XXY Klinefelter syndrome, XYY syndrome, true hermaphroditism). NamUs provides Unsure or Other categories in the application and consolidates these in our routine reporting under “Other” for instances where an individual’s biological sex is unknown, not provided, or otherwise biologically does not align with the standard biological male/female classification as exemplified above. NamUs also provides an Unsure category because in some cases of human remains, only partial remains may have been recovered and biological sex is indiscernible. Having these options allows for accurate documentation while maintaining the integrity of forensic casework.
