第2〜第4指比（2D:4D）は、ライセンスを持つテコンドー選手と年齢を合わせた運動不足の個人を区別しない

The primary aim of this study was to investigate the relationship between the second-to-fourth digit ratio (2D:4D), a putative marker of prenatal sex hormone exposure, and sports talent among children and adolescents under 18 years of age practicing taekwondo. The 2D:4D ratio is thought to reflect intrauterine testosterone and estrogen exposure, and has been associated in some studies with physical performance and athletic potential.

This cross-sectional study included licensed taekwondo athletes aged 9-17 years from Gaziantep, Turkiye, and an age-matched control group of non-athletic healthy peers. Finger lengths were measured directly using a digital caliper with 0.1 mm precision, and the 2D:4D ratios for both hands were calculated. Demographic and anthropometric data, hand and foot dominance were also recorded.

Sex-based analysis revealed that female athletes exhibited significantly higher right and left 2D:4D ratios than male athletes (p = 0.012 and p = 0.010, respectively). In the control group, females had significantly higher right and left 2D:4D ratios but lower body weight, BMI, and right and left fourth-digit lengths compared to males (p < 0.05). No significant differences were identified between sex-matched athlete and control participants (p > 0.05). Analysis according to hand and foot laterality showed no significant differences within the control group; however, right-foot-dominant athletes demonstrated significantly higher right-hand 2D:4D ratios (p = 0.022). Logistic regression analysis indicated that neither finger length nor 2D:4D ratio exerted a statistically significant effect on athletic ability (p > 0.05).

To our knowledge, this is the first study to examine the relationship between 2D:4D ratios and taekwondo performance in both male and female youth athletes in a Turkish population. The results suggest that the 2D:4D ratio may not serve as a reliable biomarker for athletic talent in this demographic. Further research including elite athletes and samples from diverse regions is warranted to confirm these findings.