Sub-Adult Sex Problem
Definition
The inability of classical morphological and metric osteological methods to determine sex in individuals below approximately 12-15 years of age, because skeletal sexual dimorphism does not develop until puberty. The solution in modern forensic practice is DNA amelogenin typing.
- Affected age range
- Below approximately 12 to 15 years
- Cause
- Skeletal dimorphism has not yet developed before puberty
- Modern solution
- DNA amelogenin gene typing
- Method limitation
- Classical morphological and metric methods are unreliable here
Common questions
Why does puberty matter so much for skeletal sex estimation?+
Sex-linked differences in the pelvis and skull that adult methods rely on, such as pelvic width or brow ridge prominence, are driven largely by hormonal changes at puberty. Before that development occurs, male and female sub-adult skeletons are much harder to tell apart by shape or measurement alone.
Is amelogenin typing always reliable for sub-adult sex determination?+
It is far more reliable than morphology but not infallible. Rare deletions on the Y-chromosome amelogenin locus can cause a genetic male to appear female in the test, so some laboratories confirm with a second sex-linked marker when the case is contested.
Related terms
- Amelogenin
- A gene on both the X and Y chromosomes used for sex determination in forensic STR kits. The X-allele amplicon is approximately...
- Discriminant Function Analysis
- A multivariate statistical technique that derives linear combinations of measurements to maximally separate two or more groups (male and female). The resulting...
- Femoral Head Vertical Diameter
- The superoinferior diameter of the femoral head, the most reliable single postcranial sex estimation measurement. US cut-offs (Stewart 1979): below 43.5 mm...
- Geometric Morphometrics
- A method that captures biological shape as a configuration of landmark coordinates, removes position/orientation/scale differences by Procrustes superimposition, and analyses the residual...
- Humeral Head Vertical Diameter
- The superoinferior diameter of the humeral head. US cut-offs (France 1998): below 43 mm female, above 47 mm male. Second most commonly...
- Khanpetch 2012
- A South-East Asian long-bone sex estimation study by Khanpetch and colleagues providing population-specific discriminant functions and cut-offs for Thai and South-East Asian...
- Procrustes Superimposition
- The statistical procedure in geometric morphometrics that removes non-shape variation (translation, rotation, scale) from a set of landmark coordinates, leaving only shape...
- Scapular Glenoid Breadth
- The anteroposterior or superoinferior diameter of the glenoid fossa on the scapula. Sexually dimorphic; discriminant functions by Dittrick and Suchey (1986) achieve...
- Stewart 1979 Cut-Offs
- The original US femoral head diameter sex classification thresholds derived by T.D. Stewart from a US military and dissection-room sample. Widely cited...