Soccer players awarded one or more red cards exhibit lower 2D:4D ratios.

Anatomical, cognitive and behavioral sex differences are widely recognized in many species. It has been proposed that some of these differences might result from the organizing effects of prenatal sex steroids. In humans, males usually exhibit higher levels of physical aggression and prowess. In this study, we analyze the relationship between second-to-fourth digit (2D:4D) ratios-a proxy for prenatal androgen levels-and foul play and sporting performance in a sample of junior soccer players from a professional Uruguayan soccer club. Our results show that the most aggressive players (i.e., those awarded one or more red cards) have a more masculine finger pattern (lower 2D:4D ratio), while no relationship could be found between sporting performance and 2D:4D ratios. The results are discussed in the context of previous findings. Aggr. Behav. 42:417-426, 2016.