Finger pointing: Why bias against 2D:4D ratios doesn't add up

Abstract

In response to our invited review of the use of digit ratios such as 2D:4D as a retrospective marker of prenatal androgen exposure, the Editor-In-Chief of this journal published a Commentary disputing the findings we had reported, citing a preprint suggesting the sex difference in digit ratios was an artifact of “allometry”, and casting doubt on a previously published meta-analysis concluding that lesbians, on average, have lower digit ratios than straight women, suggesting there may be a bias against submitting negative results. Here we respond to those points and conclude that 2D:4D of the right hand remains the best available non-invasive retrospective indicator of prenatal androgen exposure in humans. Further, we offer a new dataset replicating once again the numerous previous reports that lesbians have significantly lower right-hand 2D:4D, indicative of greater prenatal androgen exposure, than heterosexual women, and further report that the ratios of bisexual women are intermediate between those of gay and straight women, without being significantly different from either. Together with previous reports, these new data further indicate that androgens act before birth in humans to promote the likelihood of being sexually attracted to women in adulthood.