Finger-length ratios show evidence of prenatal hormone-transfer between opposite-sex twins

  title={Finger-length ratios show evidence of prenatal hormone-transfer between opposite-sex twins},
  author={Sari M. van Anders and Philip A. Vernon and Christopher J. Wilbur},
  journal={Hormones and Behavior},

Figures from this paper

Digit Ratio (2D:4D) in Twins: Heritability Estimates and Evidence for a Masculinized Trait Expression in Women from opposite-Sex Pairs
Investigation of the 2D:4D ratio of 44 men and 70 women from 36 identical and 21 fraternal twin pairs suggested that the trait is substantially heritable, consistent with a prediction from sex-hormone transfer theory.
It is argued that assortative mating on 2D:4D operates indirectly and may be mediated through the assortment on other, more perceptible, physical traits and psychological phenotypes that entertain associations with 2D-4D and are relevant for courtship and mate choice.
Finger length ratios (2D:4D) in anthropoids implicate reduced prenatal androgens in social bonding.
Test the relationship between digit ratios and behavior across nonhuman anthropoids; polygynous species, with higher levels of intrasexual competition, should have more pronounced markers of PAE (lower 2D:4D) than pair-bonded species, and results accord with those found in humans.
Intrauterine Position Effects on Anogenital Distance and Digit Ratio in Male and Female Mice
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.
No association between two candidate markers of prenatal sex hormones: digit ratios (2D:4D and other) and finger-ridge counts.
Some doubt is cast on the validity of retrospective pointers to prenatal androgen levels based on the associations of 2D:4D with finger-ridge counts, one such further under-researched marker.
The Second to Fourth Digit Ratio (2D:4D) in a Japanese Twin Sample: Heritability, Prenatal Hormone Transfer, and Association with Sexual Orientation
The existence of non-shared environmental influences that affect both 2D:4D and sexual orientation are suggested, which are in the predicted direction according to the prenatal hormone transfer hypothesis.
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.
Digit ratio (2D:4D), dominance, reproductive success, asymmetry, and sociosexuality in the BBC Internet Study
  • J. Manning, B. Fink
  • Psychology
    American journal of human biology : the official journal of the Human Biology Council
  • 2008
The BBC Internet Study of sex differences in which finger lengths were self‐measured shows sexual dimorphism, ethnic differences and higherDimorphism of right 2D:4D than left, thereby indicating that 2D-4D does measure real between‐participant variation.


Finger-Length Ratios in Female Monozygotic Twins Discordant for Sexual Orientation
Differences in 2D:4D ratio suggest that MZ twins share virtually the same genes, and lower ratio in lesbians is a result of differences in prenatal environment.
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.
Prenatal sex hormone transfer: A reason to study opposite-sex twins
Sexual orientation and the 2nd to 4th finger length ratio: evidence for organising effects of sex hormones or developmental instability?
Increased tooth crown size in females with twin brothers: Evidence for hormonal diffusion between human twins in utero
The finding that themaxillary canine, one of the most sexually dimorphic teeth, exhibits the least effect in OS female twins, suggests that prenatal sex hormone levels may have less impact on sexual dimorphism in the maxillary canines than in other permanent teeth.
2nd to 4th digit ratios, fetal testosterone and estradiol.
Are 2D:4D finger-length ratios related to sexual orientation? Yes for men, no for women.
  • R. Lippa
  • Psychology, Medicine
    Journal of personality and social psychology
  • 2003
Findings add to evidence that prenatal hormonal factors may be linked to men's sexual orientation as well as ethnic groups, after ethnicity was taken into account.
In-utero androgen exposure and 2nd to 4th digit length ratio-comparisons between healthy controls and females with classical congenital adrenal hyperplasia.
2D:4D ratios determined directly from radiographs of the left hand confirm significant differences between males and females, however, female patients with virilizing CAH do not have a male digit ratio pattern suggesting that in theleft hand digit ratio development is not influenced by in-utero exposure to androgens.
Digit length ratios predict reactive aggression in women, but not in men