PT  - JOURNAL ARTICLE
AU  - Gareth Richards
AU  - Wendy V. Browne
AU  - Mihaela Constantinescu
TI  - Digit Ratio (2D:4D) and Amniotic Testosterone and Estradiol: An Attempted Replication of Lutchmaya et al. (2004)
AID  - 10.1101/2020.07.10.197269
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.07.10.197269
4099  - http://biorxiv.org/content/early/2020/07/10/2020.07.10.197269.short
4100  - http://biorxiv.org/content/early/2020/07/10/2020.07.10.197269.full
AB  - 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 4½-year follow-up. The confidence intervals were large, the direction of correlations observed was generally erratic, and the overall findings therefore question the premise that second trimester sex hormones affect the development of digit length ratios in humans.Competing Interest StatementThe authors have declared no competing interest.