Comparison of 2D:4D Digit Ratios in Children with Specific Learning Disorders and Healthy Controls

Purpose: Prenatal androgen exposure, particularly testosterone, may play a pivotal role in shaping brain development and is hypothesised to affect intelligence and learning skills.The second-to-fourth digit ratio (2D:4D) is widely recognized as a biomarker for prenatal exposure to the androgenic hormone testosterone. The present study seeks to examine 2D:4D ratios in children diagnosed with specific learning disorder (SLD) and to assess comparatively these values with those of typically developing peers.Methods: Participants in the study were 94 children diagnosed with SLD and 57 healthy controls. Sociodemographic data were collected, and 2D:4D ratios for each hand were determined and differences between groups were examined.Results: Children diagnosed with SLD exhibited notably reduced 2D:4D digit ratios in both hands relative to typically developing peers. In the SLD group, lower 2D:4D ratios were observed in both sexes, with the difference reaching statistical significance for females’ left hand measurements.Conclusion: This evidence suggests that elevated testosterone exposure during the prenatal period may be implicated in the pathogenesis of SLD. By employing the non-invasive 2D:4D ratio, this study contributes to the growing body of evidence on biological markers associated with neurodevelopmental disorders.