Hand Asymmetry in Heterosexual and Homosexual Men and Women: Relationship to 2D:4D Digit Ratios and Other Sexually Dimorphic Anatomical Traits

  title={Hand Asymmetry in Heterosexual and Homosexual Men and Women: Relationship to 2D:4D Digit Ratios and Other Sexually Dimorphic Anatomical Traits},
  author={James Thomas Martin and David A. Puts and S. Marc Breedlove},
  journal={Archives of Sexual Behavior},
Sexual differentiation leads to the development of distinctive anatomical structures (e.g., gonads and genitalia); it also produces less obvious anatomical shifts in brain, bones, muscles, etc. This study is a retrospective analysis of growth patterns in the hands in relation to sex and sexual orientation. Using data from three published studies, we analyzed four hand traits in adults: hand width, hand length, second digit length, and fourth digit length. Using these measurements, we derived… 

Sex Differences in Directional Asymmetry of Digit Length and its Effects on Sex Differences in Digit Ratio (2D:4D)

Based on six samples totaling about 3,000 individuals, the present study replicated the first finding of Martin, Puts, and Breedlove (2008), which found leftward bias was more frequent among men and rightward bias more frequently among women, and replicated the second finding, which was smaller by orders of magnitude and not significant.

Comparative Study of Digit Ratios (2D:4D and Other) and Novel Measures of Relative Finger Length: Testing Magnitude and Consistency of Sex Differences across Samples

  • M. Voracek
  • Psychology, Biology
    Perceptual and motor skills
  • 2009
This study investigated the magnitude and cross-sample consistency of sex differences in all six possible digit ratios and in four novel relative finger-length measures suggested by Loehlin, Medland, and Martin as possibly superior to digit ratios for discriminating between the sexes.

Digit length ratio (2D/4D): comparing measurements from X-rays and photographs in field voles (Microtus agrestis)

2D/4D appears to be a rather species- and method-specific measure and researchers should be careful when generalising its applicability to study early hormonal effects in vertebrates.

Are there vocal cues to human developmental stability? Relationships between facial fluctuating asymmetry and voice attractiveness.

Segmental 2:4 digit ratio. Unilateral, bilateral and hand-type differences in men.

  • R. Khairullin
  • Medicine
    Homo : internationale Zeitschrift fur die vergleichende Forschung am Menschen
  • 2011

Pubertal Stress and Nutrition and their Association with Sexual Orientation and Height in the Add Health Data

Prenatal mechanisms are likely better candidates for explaining the height difference between gay men and heterosexual men, as well as stress, given that stress has been associated with sexual minority identification and with lower height.

Side-specific effect of yolk testosterone elevation on second-to-fourth digit ratio in a wild passerine

This is the first study which shows experimentally that early testosterone exposure can affect second-to-fourth digit ratio in a wild population of a passerine bird.


This study examined how perceptions of a person’s sexual orientation may be influenced by facial bilateral symmetry and sexually-dimorphic facial proportions thought to be influenced by sex hormones.

Second to fourth digit ratio (2D:4D) and concentrations of circulating sex hormones in adulthood

There were no strong associations between any adult circulating concentration of sex hormone or SHGB measured in adulthood and 2D:4D, and these results contribute to the growing body of evidence indicating that 2D:[4D]4D is unrelated to adult sex hormone concentrations.



Fluctuating asymmetry, second to fourth finger length ratios and human sexual orientation

  • Q. Rahman
  • Psychology, Biology
  • 2005

Sex hormones and finger length What does 2 D : 4 D indicate ?

Much recent research has focused on the ratio of the lengths of the second to fourth manual digits (2D:4D) as a predictor of the degree of expression of sexually dimorphic and other

Finger-length ratios and sexual orientation

The androgen-sensitive pattern of finger lengths is examined, and there is evidence that homosexual women are exposed to more prenatal androgen than heterosexual women are, and men with more than one older brother, who are more likely than first-born males to be homosexual in adulthood, are exposure to more pregnancies than eldest sons.

Masculinized Finger Length Patterns in Human Males and Females with Congenital Adrenal Hyperplasia

Results are consistent with the idea that prenatal androgen exposure reduces the 2D:4D and plays a role in the establishment of the sex difference in human finger length patterns, and finger lengths may offer a retrospective marker of perinatal androgens exposure in humans.

Sexual orientation and handedness in men and women: a meta-analysis.

The results support the notion that sexual orientation in some men and women has an early neurodevelopmental basis, but the factors responsible for the handedness-sexual orientation association require elucidation.

Anthropometric analysis of homosexuals and heterosexuals: implications for early hormone exposure

Dermatoglyphic asymmetry and sexual orientation in men.

An association was observed between leftward dermatoglyphic asymmetry and an increased incidence of adextrality in homosexual men, but not in heterosexual men, consistent with a biological contribution to sexual orientation.