Use of 2D:4D Digit Ratios to Determine Sex

Second to fourth digit ratios (2D:4D) are sexually dimorphic in human hands and established by the 13th gestational week. Application of 2D:4D for determining sex in living individuals by Kanchan et al. (Forensic Sci Int, 181, 2008, 53.e1) produced classification rates of 80% for males and 74–78% for females. Few studies have explored the use of 2D:4D for sexing skeletal remains. We test estimated finger lengths, phalanx lengths, and 2D:4D derived from hand bones for determining sex. Maximum phalanx length was collected using a mini‐osteometric board from 451 individuals of known age, sex, and ancestry in four skeletal collections. Logistic regression of 2nd and 4th digit finger and phalanx lengths produced classification rates greater than 80%. Digit ratios, however, failed to reach classification rates greater than 59%. Our results support those of Voracek (Forensic Sci Int, 185, 2009, e29) and suggest that 2D:4D may be population‐specific and thus inappropriate for universal application as a means of determining sex.

[1]  Baoguo Li,et al.  Digit ratio (2D:4D) and handgrip strength in subjects of Han ethnicity: impact of sex and age. , 2012, American journal of physical anthropology.

[2]  R. L. Susman.  Comparative and functional morphology of hominoid fingers. , 1979, American journal of physical anthropology.

[3]  D. Case,et al.  New siding techniques for the manual phalanges: a blind test , 2006 .

[4]  Ann H Ross,et al.  Sex Determination from Hand and Foot Bone Lengths * , 2007, Journal of forensic sciences.

[5]  P. Vr.  Relative index finger length as a sex-influenced trait in man , 1952 .

[6]  M. Cohn,et al.  Developmental basis of sexually dimorphic digit ratios , 2011, Proceedings of the National Academy of Sciences.

[7]  T. J. Thompson,et al.  Metric dimensions of the proximal phalanges of the human hand and their relationship to side, position, and asymmetry. , 2011, Homo : internationale Zeitschrift fur die vergleichende Forschung am Menschen.

[8]  W. Babler,et al.  Early prenatal attainment of adult metacarpal-phalangeal rankings and proportions. , 1975, American journal of physical anthropology.

[9]  D. Lieberman,et al.  The development of sex differences in digital formula from infancy in the Fels Longitudinal Study , 2005, Proceedings of the Royal Society B: Biological Sciences.

[10]  R. D'Agostino,et al.  A Suggestion for Using Powerful and Informative Tests of Normality , 1990 .

[11]  J. Swaddle,et al.  Digit Ratio: A Pointer to Fertility, Behavior, and Health , 2002, Heredity.

[12]  Tanuj Kanchan,et al.  Index and ring finger ratio--a new sex determinant in south Indian population. , 2008, Forensic science international.

[13]  Kevin J. MacKenzie,et al.  Finger length and distal finger extent patterns in humans. , 2002, American journal of physical anthropology.

[14]  Martin Voracek,et al.  Why digit ratio (2D:4D) is inappropriate for sex determination in medicolegal investigations. , 2009, Forensic science international.

[15]  V. Phelps.  Relative index finger length as a sex-influenced trait in man. , 1952, American journal of human genetics.

[16]  Cedric Neumann,et al.  New perspectives in the use of ink evidence in forensic science: Part I. Development of a quality assurance process for forensic ink analysis by HPTLC. , 2009, Forensic science international.

[17]  S. Menard.  Logistic Regression: From Introductory to Advanced Concepts and Applications , 2009 .

[18]  J T Manning,et al.  The ratio of 2nd to 4th digit length: a predictor of sperm numbers and concentrations of testosterone, luteinizing hormone and oestrogen. , 1998, Human reproduction.