Sexual orientation and the 2nd to 4th finger length ratio: evidence for organising effects of sex hormones or developmental instability?

  title={Sexual orientation and the 2nd to 4th finger length ratio: evidence for organising effects of sex hormones or developmental instability?},
  author={Qazi Rahman and Glenn D. Wilson},
  • Q. Rahman, G. Wilson
  • Published 1 April 2003
  • Psychology, Biology, Medicine
  • Psychoneuroendocrinology
Fluctuating asymmetry, second to fourth finger length ratios and human sexual orientation
  • Q. Rahman
  • Psychology, Biology
  • 2005
Finger Length Ratio (2D:4D) and Dimensions of Sexual Orientation
A continuous neurohormonal sexual differentiation of the brain, most notably for women, that overrides categories and results in varying dimensions of sexual orientation is hypothesized.
Prenatal Influences on Sexual Orientation: Digit Ratio (2D:4D) and Number of Older Siblings
Prenatal androgen levels are suggested to influence sexual orientation in both sexes. The 2D:4D digit ratio has been found to associate with sexual orientation, but published findings have often been
Hand Asymmetry in Heterosexual and Homosexual Men and Women: Relationship to 2D:4D Digit Ratios and Other Sexually Dimorphic Anatomical Traits
The present evidence actually suggests that homosexuals have lower FA than heterosexuals, raising the question of whether the positive fitness components associated with low FA may contribute to selection that maintains homosexuality in a population.
Sexual orientation and the second to fourth finger length ratio: a meta-analysis in men and women.
It is found that heterosexual women had higher (more feminine) left- and right-hand 2D:4D than did lesbians, but there was no difference between heterosexual and gay men.
Sexual Orientation and Fluctuating Asymmetry in Men and Women
Although elevated levels of developmental stress appear to be linked to shifts in sexual orientation, the underlying mechanism does not seem to be connected to sex-atypical prenatal hormones.


The ratio of 2nd to 4th digit length and male homosexuality.
  • Robinson, Manning
  • Psychology, Medicine
    Evolution and human behavior : official journal of the Human Behavior and Evolution Society
  • 2000
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.
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.
Neurohormonal functioning and sexual orientation: a theory of homosexuality-heterosexuality.
Evidence indicating that the process of determining human sexual orientation is fundamentally the same in all mammals is reviewed, and a theory of how the entire spectrum of humanSexual orientation is determined is proposed.
The 2nd:4th digit ratio, sexual dimorphism, population differences, and reproductive success. evidence for sexually antagonistic genes?
  • Manning, Barley, Szwed
  • Psychology
    Evolution and human behavior : official journal of the Human Behavior and Evolution Society
  • 2000
The Structure of Sexual Orientation and its Relation to Masculinity, Femininity, and Gender Diagnosticity: Different for Men and Women
Three hundred ninety-four college students (148 men and 246 women; 42% White, 25% Hispanic, and 23% Asian) were assessed on masculine instrumentality (M), feminine expressiveness (F), gender
The 2nd:4th digit ratio and asymmetry of hand performance in Jamaican children
Testosterone, particularly prenatal testosterone, has been implicated in the aetiology of many extragenital sexually dimorphic traits and it is suggested that the 2D:4D ratio may be associated with the expression of other sexuallyDimorphic behavioural traits.