## 4 Discussion
### Analysis by Age Groups and Gender Differences  
In this regard, the findings of this study indicate the presence of a small but persistent RAE in almost all age groups established by the FEDO, except for the female elite category. In the M-16 category, a detailed analysis of the distribution by birth quartiles(Table 5) shows no significant differences between athletes. This result suggests that, in this specific category, the RAE is not clearly detected when athletes are segmented by quarters (Q1 to Q4). However, when the analysis is performed considering the semesters of birth (Figure 3), significant differences are identified, indicating that this broader segmentation approach (S1 vs. S2) captures distribution patterns that are not as evident when segmented into quartiles. This finding could be explained by the less detailed nature of quartiles compared to the more generalized division of semesters, which allows for a clearer view of how athletes born in the first half of the year (S1) generally have a relative advantage compared to those born in the second half of the year (S2), regardless of the quartiles in which they are grouped. On the other hand, there was an overrepresentation of athletes born in the first semester (S1) in the mixed U-10 category, as well as in both female (Figure 2) and male categories (Figure 3). Typically, the presence or absence of RAE is examined by comparing the birth date distribution of athletes with that of the general population, provided that the premise holds that the population of licensed athletes reflects that distribution [2]. However, the results of this study suggest that, in Spanish orienteering, there is a moderate disparity in the birth date distribution between licensed athletes, from the U-10 category to the adult category, except for the female elite category. Regarding the effect size, the values obtained are generally comparable between female and male categories--except for the elite category--without observing a systematic trend (neither increasing nor decreasing) as athletes move from younger to older categories, whether analyzing the data in quartiles or semesters. While it is commonly assumed that RAE is less pronounced in female sports due to less competition [2] and that maturational advantages have less of an impact on women [73], the results of this study indicate that RAE manifests consistently in both sexes, in contrast to previous studies [9; 74; 75]. [PERSON] et al. [9] conducted a meta-analysis of 57 studies spanning 25 sports, revealing a significant but small RAE in female athletes, with a higher magnitude observed in pre-adolescents (\(\leq\)11 years), adolescents (12-14 years), and at higher competition levels. The effect was more pronounced in sports with high physiological demands. Similarly, [PERSON] et al. [74] found that RAE was present in Spanish female athletics, though its influence was weaker than in male athletics and was only detected in youth and absolute categories. [PERSON] et al. [75] examined RAE in the German handball talent development system, finding notable differences between males and females. In men, RAE was strongest at the initial selection stage and gradually weakened as the competition level increased, becoming negligible at the senior national team level. In contrast, while RAE was initially weaker in female athletes, its effect intensified in later stages, particularly in youth national teams, before balancing out at the senior level. This pattern suggests that selection pressures may differ by sex, with early-stage competition being more pronounced in males, whereas increased competitiveness in later stages might exacerbate RAE in females. Taken together, these studies suggest that while RAE is generally less pronounced in female athletes, its presence is modulated by sport-specific and contextual factors. In contrast, our findings indicate a more consistent manifestation of RAE across both sexes in orienteering, challenging the notion that it is inherently weaker in female sports.