This chapter presents the main concepts of sporting inclusion and sporting exclusion, and explains human differences such as sex, gender, disability and race. It talks about major dimensions of the inclusion/exclusion debate in sport because human differences raise important points about performance enhancement, the integrity of sport, matching ability, safety and the sporting culture. Culture reflects both the 'biological endowment of humans', as well as the 'constraints of their social and physical environments'. Research relating to the human body and sport has traditionally been found in the sciences, such as anatomy, kinesiology, biomechanics and physiology. Within sport, one's differences are much more pronounced when they are considered in light of sport-specific inclusion and exclusion. Clear definitions of human differences become important when an athlete is being included or excluded on the basis of biological or cultural markers.