Methods used for biological sex identification

A more prominent brow ridge (supraorbital torus).

A square rather than round chin and a larger jaw angle.

Long Bones (Metric Analysis): Measuring the overall size, length, and diameter of bones like the femur and humerus. Males generally have longer and thicker long bones to support greater body mass and muscle attachment.

2. What is Photo-Superimposition?

Photo-superimposition is a forensic technique used primarily in human identification and pattern analysis by aligning two or more images taken at different times or from different sources.

Mechanism and Purpose

Definition: It involves laying one image (e.g., an image of a skull) over another image (e.g., a known photograph of a missing person taken during life) to check for consistent alignment and points of correspondence.

Technique: Modern photo-superimposition is done digitally. The known ante-mortem photograph is correctly scaled and oriented to the dimensions of the post-mortem skull image. The two images are then semi-transparently superimposed.

Identification Goal: The goal is to determine if the skull's morphological features—such as the outline of the eye orbits, the shape of the nasal opening, the placement of the chin, and the dental features—match the corresponding features visible in the photograph. A precise match indicates that the skull and the photograph likely belong to the same individual, providing supporting evidence for a positive identification.

Other Uses: The technique can also be used to align injury patterns (e.g., tool marks on bone) with suspected implements, or to align vehicle damage with accident scenes.

Sample Answer

Methods Used for Biological Sex Identification

Biological sex identification, particularly in forensic, anthropological, and clinical contexts, relies on examining several aspects of the human body.1 The methods used depend heavily on the type and completeness of the biological material available.2

A. Non-Skeletal (Soft Tissue) Methods

These are typically used for living individuals or recent remains:

Genital Examination: Direct observation of external primary sex characteristics.

Chromosomal/Genetic Analysis: Analyzing Sex Chromosomes (3$\text{XX}$ for female, 4$\text{XY}$ for male).5 This is the definitive biological method and can be done using DNA from any tissue (blood, saliva, hair, semen, bone).

Hormone Levels: Measuring concentrations of sex hormones like estrogen and progesterone (higher in typical adult females) or testosterone (higher in typical adult males).

B. Skeletal (Hard Tissue) Methods (Forensic/Anthropology)6

When only skeletal remains are available, sex is estimated by analyzing sexually dimorphic (size and shape differences) features:7

Pelvis (Most Reliable): The female pelvis is wider, shallower, and rounder to facilitate childbirth (e.g., wider sciatic notch, wider subpubic angle $\text{> }90^\circ$). The male pelvis is narrower and deeper.

Skull: Males typically have larger, more robust features, including:

Larger mastoid processes (behind the ear).8

A more pronounced, sloping forehead (frontal bone).