Skip to main content
Log in

The Second to Fourth Digit Ratio (2D:4D) in a Japanese Twin Sample: Heritability, Prenatal Hormone Transfer, and Association with Sexual Orientation

  • Original Paper
  • Published:
Archives of Sexual Behavior Aims and scope Submit manuscript

Abstract

The second to fourth digit ratio has been argued to reflect prenatal hormonal influences and is reportedly associated with various psychological and behavioral traits, such as sexual orientation, cognitive abilities, and personality. We examined genetic and environmental influences on the second to fourth digit ratio (2D:4D) using a Japanese twin sample (N = 300). The genetic analysis showed substantial additive genetic influences for both right and left hand 2D:4D. The rest of the variance was explained mainly by environmental influences not shared within twin pairs. These findings were, in general, in accordance with preceding studies with primarily Caucasian twin samples. The bivariate genetic analysis revealed that the additive genetic influences were largely shared between the right and left hand, while the non-shared environmental influences were largely unique to each hand. Results from a comparison of opposite-sex and same-sex twins were not significant, although they were in the predicted direction according to the prenatal hormone transfer hypothesis. Female monozygotic twin pairs discordant in sexual orientation showed significant within-pair differences in left hand 2D:4D, where non-heterosexual twins had lower (more masculinized) 2D:4D. In addition, we found that non-heterosexual male MZ twins had larger (more feminized) 2D:4D than their heterosexual co-twins. These results suggest the existence of non-shared environmental influences that affect both 2D:4D and sexual orientation.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1

Similar content being viewed by others

References

  • Akaike, H. (1987). Factor analysis and AIC. Psychometrika, 52, 317–332. doi:10.1007/BF02294359.

    Article  Google Scholar 

  • Austin, E. J., Manning, J. T., McInroy, K., & Mathews, E. (2002). A preliminary investigation of the associations between personality, cognitive ability and digit ratio. Personality and Individual Differences, 33, 1115–1124. doi:10.1016/S0191-8869(02)00002-8.

    Article  Google Scholar 

  • Blanchard, R. (2001). Fraternal birth order and the maternal immune hypothesis of male homosexuality. Hormones and Behavior, 40, 105–114. doi:10.1006/hbeh.2001.1681.

    Article  PubMed  Google Scholar 

  • Blanchard, R., & Klassen, P. (1997). H-Y antigen and homosexuality in men. Journal of Theoretical Biology, 185, 373–378. doi:10.1006/jtbi.1996.0315.

    Article  PubMed  Google Scholar 

  • Bogaert, A. F., & Skorska, M. (2011). Sexual orientation, fraternal birth order, and the maternal immune hypothesis: A review. Frontiers in Neuroendocrinology, 32, 247–254. doi:10.1016/j.yfrne.2011.02.004.

    Article  PubMed  Google Scholar 

  • Cohen-Bendahan, C. C. C. (2005). Biological roots of sex differences: A longitudinal twin study. Doctoral dissertation, University Medical Center, Utrecht, The Netherlands.

  • Gobrogge, K., Breedlove, S., & Klump, K. (2008). Genetic and environmental influences on 2D:4D finger length ratios: A study of monozygotic and dizygotic male and female twins. Archives of Sexual Behavior, 37, 112–118. doi:10.1007/s10508-007-9272-2.

    Article  PubMed  Google Scholar 

  • Grimbos, T., Dawood, K., Burriss, R. P., Zucker, K. J., & Puts, D. A. (2010). Sexual orientation and the second to fourth finger length ratio: A meta-analysis in men and women. Behavioral Neuroscience, 124, 278–287. doi:10.1037/a0018764.

    Article  PubMed  Google Scholar 

  • Hall, L. S., & Love, C. T. (2003). Finger-length ratios in female monozygotic twins discordant for sexual orientation. Archives of Sexual Behavior, 32, 23–28.

    Article  PubMed  Google Scholar 

  • Hoekstra, C., Zhao, Z. Z., Lambalk, C. B., Willemsen, G., Martin, N. G., Boomsma, D. I., et al. (2008). Dizygotic twinning. Human Reproduction Update, 14, 37–47. doi:10.1093/humupd/dmm036.

    Article  PubMed  Google Scholar 

  • Hönekopp, J., Manning, J. T., & Müller, C. (2006). Digit ratio (2D:4D) and physical fitness in males and females: Evidence for effects of prenatal androgens on sexually selected traits. Hormones and Behavior, 49, 545–549. doi:10.1016/j.yhbeh.2005.11.006.

  • Hönekopp, J., & Watson, S. (2010). Meta-analysis of digit ratio 2D:4D shows greater sex difference in the right hand. American Journal of Human Biology, 22, 619–630. doi:10.1002/ajhb.21054.

    Article  PubMed  Google Scholar 

  • Imaizumi, Y. (2001). Estimated number of multiplets under 16 years using two sets of census data in Japan: 1990 and 1995. Twin Research, 4, 232–237. doi:10.1375/1369052012443.

    Article  PubMed  Google Scholar 

  • Klein, F., Sepekoff, B., & Wolf, T. J. (1985). Sexual orientation: A multi-variable dynamic process. Journal of Homosexuality, 11, 35. doi:10.1300/J082v11n01_04.

    Article  PubMed  Google Scholar 

  • Lippa, R. A. (2003). Are 2D:4D finger-length ratios related to sexual orientation? Yes for men, no for women. Journal of Personality and Social Psychology, 85, 179–188. doi:10.1037/0022-3514.85.1.179.

    Article  PubMed  Google Scholar 

  • Lippa, R. A. (2006). Finger lengths, 2D:4D ratios, and their relation to gender-related personality traits and the Big Five. Biological Psychology, 71, 116–121. doi:10.1016/j.biopsycho.2005.02.004.

    Article  PubMed  Google Scholar 

  • Loehlin, J., Medland, S., & Martin, N. (2009). Relative finger lengths, sex differences, and psychological traits. Archives of Sexual Behavior, 38, 298–305. doi:10.1007/s10508-007-9303-z.

    Article  PubMed  Google Scholar 

  • Manning, J. T., Barley, L., Walton, J., Lewis-Jones, D. I., Trivers, R. L., Singh, D., et al. (2000). The 2nd:4th digit ratio, sexual dimorphism, population differences, and reproductive success: Evidence for sexually antagonistic genes? Evolution and Human Behavior, 21, 163–183. doi:10.1016/S1090-5138(00)00029-5.

    Article  PubMed  Google Scholar 

  • Manning, J. T., Bundred, P. E., & Mather, F. M. (2004a). Second to fourth digit ratio, sexual selection, and skin colour. Evolution and Human Behavior, 25, 38–50. doi:10.1016/S1090-5138(03)00082-5.

    Article  Google Scholar 

  • Manning, J. T., Bundred, P. E., Newton, D. J., & Flanagan, B. F. (2003a). The second to fourth digit ratio and variation in the androgen receptor gene. Evolution and Human Behavior, 24, 399–405. doi:10.1016/S1090-5138(03)00052-7.

    Article  Google Scholar 

  • Manning, J. T., Churchill, A. J. G., & Peters, M. (2007). The effects of sex, ethnicity, and sexual orientation on self-measured digit ratio (2D:4D). Archives of Sexual Behavior, 36, 223–233. doi:10.1007/s10508-007-9171-6.

    Article  PubMed  Google Scholar 

  • Manning, J., Henzi, P., Venkatramana, P., Martin, S., & Singh, D. (2003b). Second to fourth digit ratio: Ethnic differences and family size in English, Indian and South African populations. Annals of Human Biology, 30, 579.

    Article  PubMed  Google Scholar 

  • Manning, J. T., & Robinson, S. J. (2003). 2nd to 4th digit ratio and a universal mean for prenatal testosterone in homosexual men. Medical Hypotheses, 61, 303–306. doi:10.1016/S0306-9877(03)00184-1.

    Article  PubMed  Google Scholar 

  • Manning, J., Scutt, D., & Lewis-Jones, D. (1998). Developmental stability, ejaculate size, and sperm quality in men. Evolution and Human Behavior, 19, 273–282. doi:10.1016/S1090-5138(98)00024-5.

    Article  Google Scholar 

  • Manning, J., Stewart, A., Bundred, P., & Trivers, R. (2004b). Sex and ethnic differences in 2nd to 4th digit ratio of children. Early Human Development, 80, 161–168. doi:10.1016/j.earlhumdev.2004.06.004.

    Article  PubMed  Google Scholar 

  • Manning, J. T., & Taylor, R. P. (2001). Second to fourth digit ratio and male ability in sport: Implications for sexual selection in humans. Evolution and Human Behavior, 22, 61–69. doi:10.1016/S1090-5138(00)00063-5.

    Article  PubMed  Google Scholar 

  • McFadden, D., Loehlin, J. C., Breedlove, S. M., Lippa, R. A., Manning, J. T., & Rahman, Q. (2005). A reanalysis of five studies on sexual orientation and the relative length of the 2nd and 4th fingers (the 2D:4D ratio). Archives of Sexual Behavior, 34, 341–356. doi:10.1007/s10508-005-3123-9.

    Article  PubMed  Google Scholar 

  • McFadden, D., & Shubel, E. (2002). Relative lengths of fingers and toes in human males and females. Hormones and Behavior, 42, 492–500. doi:06/hbeh.2002.1833.

    Article  PubMed  Google Scholar 

  • McIntyre, M. H., Cohn, B. A., & Ellison, P. T. (2006). Sex dimorphism in digital formulae of children. American Journal of Physical Anthropology, 129, 143–150. doi:10.1002/ajpa.20240.

    Article  PubMed  Google Scholar 

  • Medland, S. E., & Loehlin, J. C. (2008). Multivariate genetic analyses of the 2D:4D ratio: Examining the effects of hand and measurement technique in data from 757 twin families. Twin Research and Human Genetics, 11, 335–341. doi:10.1375/twin.11.3.335.

    Article  PubMed  Google Scholar 

  • Medland, S. E., Loehlin, J. C., & Martin, N. G. (2008). No effects of prenatal hormone transfer on digit ratio in a large sample of same- and opposite-sex dizygotic twins. Personality and Individual Differences, 44, 1225–1234. doi:10.1016/j.paid.2007.11.017.

    Article  Google Scholar 

  • Neale, M. C., Boker, S. M., Xie, G., & Maes, H. H. (2004). Mx: Statistical modelling (6th ed.). Richmond, VA: Virginia Commonwealth University, Department of Psychiatry. Retrieved from http://www.vipbg.vcu.edu/~vipbg/software/mxmanual.pdf.

  • Neale, M. C., & Maes, H. H. M. (2002). Methodology for genetic studies of twins and families. Dordrecht: Kluwer.

    Google Scholar 

  • Ooki, S., Yamada, K., Asaka, A., & Hayakawa, K. (1990). Zygosity diagnosis of twins by questionnaire. Acta Geneticae Medicae et Gemellologiae, 39, 109–115.

    PubMed  Google Scholar 

  • Paul, S. N., Kato, B. S., Cherkas, L. F., Andrew, T., & Spector, T. D. (2006). Heritability of the second to fourth digit ratio (2d:4d): A twin study. Twin Research and Human Genetics, 9, 215–219. doi:10.1375/twin.9.2.215.

    Article  PubMed  Google Scholar 

  • Peters, M., Manning, J. T., & Reimers, S. (2007). The effects of sex, sexual orientation, and digit ratio (2D:4D) on mental rotation performance. Archives of Sexual Behavior, 36, 251–260. doi:10.1007/s10508-006-9166-8.

    Article  PubMed  Google Scholar 

  • Plomin, R., DeFries, J. C., McClearn, G. E., & McGuffin, P. (2008). Behavioral genetics (5th ed.). New York: Worth Publishers.

    Google Scholar 

  • Puts, D., McDaniel, M., Jordan, C., & Breedlove, S. (2008). Spatial ability and prenatal androgens: Meta-analyses of congenital adrenal hyperplasia and digit ratio (2D:4D) studies. Archives of Sexual Behavior, 37, 100–111.

    Article  PubMed  Google Scholar 

  • Putz, D. A., Gaulin, S. J. C., Sporter, R. J., & McBurney, D. H. (2004). Sex hormones and finger length: What does 2D:4D indicate? Evolution and Human Behavior, 25, 182–199. doi:10.1016/j.evolhumbehav.2004.03.005.

    Article  Google Scholar 

  • Shikishima, C., Ando, J., Ono, Y., Toda, T., & Yoshimura, K. (2006). Registry of adolescent and young adult twins in the tokyo area. Twin Research and Human Genetics, 9, 811–816. doi:10.1375/twin.9.6.811.

    Article  PubMed  Google Scholar 

  • Turkheimer, E. (2000). Three laws of behavior genetics and what they mean. Current Directions in Psychological Science, 9, 160–164. doi:10.1111/1467-8721.00084.

    Article  Google Scholar 

  • van Anders, S. M., Vernon, P. A., & Wilbur, C. J. (2006). Finger-length ratios show evidence of prenatal hormone-transfer between opposite-sex twins. Hormones and Behavior, 49, 315–319. doi:10.1016/j.yhbeh.2005.08.003.

    Article  PubMed  Google Scholar 

  • Voracek, M., & Dressler, S. G. (2007). Digit ratio (2D:4D) in twins: Heritability estimates and evidence for a masculinized trait expression in women from opposite-sex pairs. Psychological Reports, 100, 115–126.

    Article  PubMed  Google Scholar 

  • Voracek, M., & Dressler, S. G. (2009). Familial resemblance in digit ratio (2D:4D). American Journal of Physical Anthropology, 140, 376–380. doi:10.1002/ajpa.21105.

    Article  PubMed  Google Scholar 

  • Williams, T. J., Pepitone, M. E., Christensen, S. E., Cooke, B. M., Huberman, A. D., Breedlove, N. J., et al. (2000). Finger-length ratios and sexual orientation. Nature, 404, 455–456. doi:10.1038/35006555.

    Article  PubMed  Google Scholar 

Download references

Acknowledgments

We would like to express our gratitude to the twins registered with the Keio Twin Registry who participated in the study. This study was supported in part by Grant-in-Aid for Scientific Research (B) (16330133) by the Japanese Ministry of Education, Culture, Sports, Science and Technology, by the Centre for Integrated Research on the Mind at Keio University, and by the collaborative research project at Kokoro Research Center at Kyoto University.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Kai Hiraishi.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Hiraishi, K., Sasaki, S., Shikishima, C. et al. The Second to Fourth Digit Ratio (2D:4D) in a Japanese Twin Sample: Heritability, Prenatal Hormone Transfer, and Association with Sexual Orientation. Arch Sex Behav 41, 711–724 (2012). https://doi.org/10.1007/s10508-011-9889-z

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10508-011-9889-z

Keywords

Navigation