Second to fourth digit (2D:4D) ratio and their relationships among first-time mother-and-child population in Ghana

Abstract The study aimed to determine the 2D:4D digit ratios and their relationships in a paired mother-and-child population. This was a cross-sectional study from December 2020 to January 2021. Digit ratios were measured by computer-assisted analysis (GIMP). Outcome variables were compared by < mean versus ≥ mean of digit ratios. The study involved 84 mother-and-child pairs (male: 45). The mean ± SD age of mothers was 23.5 ± 3.58 years. The median (IQR) age of female children was 111(51–180) days and males, 74 (44–190) days. The mean ± SD right-hand 2D:4D ratio was 0.94 ± 0.04 for mothers, 0.91 ± 0.04 for female and 0.90 ± 0.04 for male children. The mean ± SD left-hand 2D:4D ratios were 0.93 ± 0.04 for mothers, 0.92 ± 0.04 for female and 0.93 ± 0.05 for male children. Male and female children did not differ in their 2D:4D digit ratios, but males showed leftward bias. Mothers’ right-hand digit ratio correlated with that of daughters’ (r = 0.52, P = 0.001) and sons’ (r = 0.38, P = 0.011). Serum alanine transferase (ALT) levels were positively associated with ≥ mean 2D:4D ratios of the right [aOR: 1.081(1.009–1.159)] and the left-hand [aOR:1.198(1.084–1.325)] of mothers. A mother’s height could be predicted from their 2D:4D ratios. These findings support the heritability of 2D:4D ratios. We, however, recommend further studies.