Abstract
This chapter discusses the sex category in sport from a sport-respecting stance. It outlines existing sport structures - how sport is an activity that compares bodily capacities through structured competition, created by constitutive rules that prescribe sports justice; and how eligibility rules derive from constitutive rules. The main function of eligibility rules is inclusion, since rules are designed to make the sport accessible to athletes with different bodily characteristics. The logic of categorization of athletes that conditions eligibility rules for a particular sport or discipline must be partly based on practical concerns (such as athlete numbers) and partly on considering the values of inclusion, fairness and safety. At present, this results in categories based on sex, age, dis/ability and weight. A rationale for the sex category addresses the historical development of eligibility rules, problems with female athlete verification, and challenges posed by transgender and intersex athletes. Problems with sport categorization terminology are discussed, especially the conflation of sex and gender, revealing some contemporary misunderstandings. The final section explores and critiques different categorization suggestions as a substitute for the sex category, including unisex sport, an open category, handicap systems, categories based on bodily characteristics (e.g. height) and categorization based on gender or genealogy.