ABSTRACT Background Variation in exposure to prenatal androgens was linked with athletic abilities and varied performance in different sports. The ratio between the second and fourth digit lengths (2D:4D) is a proxy indicator of prenatal testosterone exposure. A higher exposure leads to a lower 2D:4D and vice versa. Negative associations between digit ratio and several sports performances were consistent in earlier research. Aim The aim of the present study was to assess if 2D:4D was lower among the Polish competitive swimmers compared to non‐sporting individuals and the heterogeneity in sex difference among different levels of swimmers and the non‐sporting group. Method This cross‐sectional study assessed 2D:4D among two groups of swimmers from the Polish national team and other higher level swimmers, and a control group (54 males and 34 females). Height, weight, and lengths of 2D and 4D were measured. Results The control group showed a significant sex difference in the right hand 2D:4D; the females showed a higher ratio than the males ( t = 2.17, p < 0.05). However, no sex difference was evident in any of the swimmers' groups. The difference in 2D:4D among the three study groups was significant only for the left 2D:4D in males and only for the right 2D:4D in females. The female swimmers (both national and general) showed significantly lower right 2D:4D than the control females, whereas the male swimmers showed significantly lower left 2D:4D than the control males. Conclusion The swimmers had lower 2D:4D than non‐sporting individuals; the top level swimmers had the lowest 2D:4D. The female swimmers, particularly the elite group, showed “masculine” 2D:4D similar to their male counterparts. A plausible positive selection for a masculinised digit ratio (higher prenatal testosterone exposure) among the females in highly competitive professional sports was hypothesized.
Kociuba et al. (2026) studied this question.