Resumen:
To what extent is European professional soccer affected by the Relative Age Effect (RAE)? The relative age effect (RAE) consists of the lower presence in any given area, of those born in the last months closer to the cut-off date, from which a new age category is classified. In the scope of sports and, specifically soccer, the unequal representation of athletes according to their age and birth month is a matter of concern. This research aims to analyze the birth dates distribution and RAE by position in the top 10 clubs in the UEFA ranking at the end of the 2020/2021 season.