Throughout history fighting has been associated with men. Cross-cultural studies of male/female differences have found serious violence as the most distinctive sex difference there is. Is that a matter of education and social conventions, or are men naturally far more adapted to fighting than women are? This question is at the centre of public debate nowadays regarding the right and ability of women to enlist in combat roles in the armed services. The article attempts to elucidate the nature of the biocultural interactions involved, whose complexity, and even existence, are all too often ignored in the debate.