A meta-analysis on 2D:4D and athletic prowess: Substantial relationships but neither hand out-predicts the other

We meta-analyzed the literature on the relationship between the length ratio of the second to the fourth digit (2D:4D), a putative negative correlate of prenatal testosterone (T) levels in humans, and athletic prowess. Analyses of ⩾21 samples with ⩾ 2527 participants revealed: (i) measures of athletic prowess are reliably negatively linked to 2D:4D in both hands in females and males (r ≈ −.26, p < .001); (ii) considerable heterogeneity of results suggests that prenatal T has inconsistent, low to moderate effects on athletic prowess; (iii) contrary to popular claims, no hand systematically out-predicted the other hand in the domain of athletic prowess (p = .957), which implies that researchers should always study 2D:4D in both hands. However, systematic heterogeneity in this latter result suggests that under some circumstances yet to be identified, left-hand 2D:4D systematically out-predicts right-hand 2D:4D whereas the opposite is true under other circumstances.