Summary Estimating Sex - [LEC 9]

M2: The Biological Profile



Lecture 9
Estimating Sex


PART 1 – SEX SPECIFIC ASPECTS OF PELVIC
ANATOMY
 (1) The basic elements of an initial forensic examination
should…
o Identify basic demographic information about decedent (person
ELEMENTS OF A who died)
FORENSIC o Screen for features leading to a positive identification (an exact
person identified)
INVESTIGATION  (2) Reconstruct cause of death, manner of death, help interpret
crime scene
o UNIT 3


 SEXING
o Discriminating between “male” and “female”
o There are metric and non-metric ways of determining sex
o Involves sexual dimorphism
DETERMINING  AGING
o Estimation of an individual’s age at death
AGE, SEX,
① Absolute Age
ANCESTRY, AND ② Age Class
STATURE FROM ③ Seriation – relative age; place in order: youngest to oldest
SKELETAL  ANCESTRY
o Estimation of an individual’s heritage
REMAINS
 ESTIMATING STATURE
o Determining height of an individual
o Based on creating a relationship of some measurable features to
that on an individual of known height: REGRESSION ANALYSIS


FORENSIC  (1) Identify his or her sex
o Eliminates 50% of the population of missing persons from
INVESTIGATION consideration for a John Doe/Jane Doe
PHASE 1: o Since women give birth structure of pelvis reflects this
BASIC o Also based in the fact that men are larger than women 
INFORMATION based on evolutionary history of monogamy


 Determining biological sex
 Male, Female, Or Indeterminate
“SEXING” A  Based on degree of sexual dimorphism in a population
SKELETON  Note that sex ≠gender
o Sex = Biological Term

, M2: The Biological Profile


o Gender = Social Term


 METRIC
o Dimensions with breakpoints
o Ex.) max diameter of humeral or femoral head
METHODS  NONMETRIC
o Pelvic Morphology
o Cranial Morphology


 SEXUAL DIMORPHISM
o “Sex-Based Two Forms”
o The tendency for males and females of a species to vary in size,
with males being larger in primates
o In most primates  males will be larger than females




SEXUAL
DIMORPHISM




 Order of Accuracy
ASSESSING SEX o Pelvis – primary sexual characteristics
FROM THE o Cranium – secondary sexual characteristics
SKELETON o Postcranium and Dentition – based on sexual dimorphism


 Sex characteristics of the skeleton are not well developed until
adolescence and beyond
ADULTS ONLY  Although some methods of sexing subadults have been advanced, none
has been tested adequately and accepted


 Pelvis differences reflect primary sexual characteristics 
PARTURITION
 Can be 95% Accurate
PELVIC
MORPHOLOGY SUB-PUBIC ANGLE
 Females have a wider sub-pubic angle than males