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Digit ratio (2D:4D) and amniotic testosterone and estradiol: An attempted replication of Lutchmaya et al. (2004)

Lookup NU author(s): Dr Gareth RichardsORCiD



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


The ratio of length between the second (index) and fourth (ring) fingers (digit ratio or 2D:4D) is frequently employed as a retrospective marker of prenatal sex hormone exposure. Lutchmaya et al. (2004) reported that the ratio of testosterone (T) to estradiol (E) present in second trimester amniotic fluid was negatively correlated with digit ratios for the right hand (but not the left hand) in a sample of 29 children at 2-year follow-up. This observation is frequently cited as evidence for the measure’s validity but has not been replicated. We therefore present the findings of another study of amniotic T and E that did not find evidence for these effects at 4.5-year follow-up. The confidence intervals were large, the direction of correlations observed was generally erratic, and the overall findings question the premise that second trimester sex hormones affect the development of digit length ratios in humans.

Publication metadata

Author(s): Richards G, Browne WV, Constantinescu M

Publication type: Article

Publication status: Published

Journal: Journal of Developmental Origins of Health and Disease

Year: 2021

Volume: 12

Issue: 6

Pages: 859-864

Print publication date: 01/12/2021

Online publication date: 21/01/2021

Acceptance date: 25/11/2020

Date deposited: 25/11/2020

ISSN (print): 2040-1744

ISSN (electronic): 2040-1752

Publisher: Cambridge University Press


DOI: 10.1017/S2040174420001294


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