Finger-length ratios and sexual orientation

@article{Williams2000FingerlengthRA,
  title={Finger-length ratios and sexual orientation},
  author={Terrance J. Williams and Michelle E. Pepitone and Scott E. Christensen and Bradley M. Cooke and Andrew D Huberman and Nicholas J. Breedlove and Tessa J. Breedlove and Cynthia L. Jordan and Stephen M. Breedlove},
  journal={Nature},
  year={2000},
  volume={404},
  pages={455-456}
}
Animal models have indicated that androgenic steroids acting before birth might influence the sexual orientation of adult humans. Here we examine the androgen-sensitive pattern of finger lengths, and find evidence that homosexual women are exposed to more prenatal androgen than heterosexual women are; also, men with more than one older brother, who are more likely than first-born males to be homosexual in adulthood, are exposed to more prenatal androgen than eldest sons. Prenatal androgens may… 
Anthropometric analysis of homosexuals and heterosexuals: implications for early hormone exposure
TLDR
The data support the hypothesis that male homosexuals have had less steroid exposure during development than male heterosexuals and that female homosexuals have have had greater steroid exposure During development than their heterosexual counterparts.
Fluctuating asymmetry, second to fourth finger length ratios and human sexual orientation
  • Q. Rahman
  • Medicine, Psychology
    Psychoneuroendocrinology
  • 2005
TLDR
Examining nine bilateral somatic traits in 120 healthy heterosexual and homosexual men and women found that sexual orientation did not relate to composite FA scores, which constrain the number of possible neurodevelopmental pathways responsible for sexual orientation in humans.
Prenatal Influences on Sexual Orientation: Digit Ratio (2D:4D) and Number of Older Siblings
  • K. Kangassalo, M. Pölkki, M. Rantala
  • Psychology, Medicine
    Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior
  • 2011
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
Sexual orientation and the 2nd to 4th finger length ratio: evidence for organising effects of sex hormones or developmental instability?
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The evidence may suggest that homosexual males and females have been exposed to non-disruptive, but elevated levels of androgens in utero, but these data also draw attention to difficulties in the interpretation of results when somatic features are employed as biological markers of prenatal hormonal influences.
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Publisher Summary This chapter summarizes representative works from areas of inquiry that enlarge understanding of this unique aspect of human development. Focus areas include genetics research,
Minireview: Hormones and human sexual orientation.
TLDR
It seems therefore that the prenatal endocrine environment has a significant influence on human sexual orientation but a large fraction of the variance in this behavioral characteristic remains unexplained to date.
Differences in Finger Length Ratios Between Self-Identified “Butch” and “Femme” Lesbians
TLDR
It is concluded that increased early androgen exposure plays a role in only some cases of female homosexuality, and that the sexual orientation of “femme” lesbians is unlikely to have been influenced by early androgens.
Prenatal Influences on Human Sexual Orientation: Expectations versus Data
  • S. Breedlove
  • Psychology, Medicine
    Archives of sexual behavior
  • 2017
TLDR
The data indicate that human sexual orientation is sufficiently polarized that groups of lesbians show evidence of greater prenatal androgen exposure than groups of straight women, while groups of gay men have, on average, a greater proportion of brothers among their older siblings than do straight men.
Intrauterine Position Effects on Anogenital Distance and Digit Ratio in Male and Female Mice
TLDR
The lack of correlation between 2D:4D and AGDs in this mouse strain suggests that these two measures do not reflect a common influence of androgen exposure, and the possible roles of temporal and localized effects of masculinization are discussed.
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