Even as barriers impeding participation in sports by women are eliminated, differences between male and female including gender-segregated competitions and different rules still exist. Mixed martial arts (MMA) competitions, which have been gaining popularity since the 1990s in both Japan and the United States, are held under different rules for the different genders. There are more restrictions (prohibitions) in the rules for female than those for male. MMA is dangerous in the sense that the objective is to knock out the opponent or to force the opponent to give up. The author examined the types of conduct that are prohibited in MMA, which entails these risks, because they are dangerous, and whether there are any differences between competitions for male and female. For this research, the author analyzed the rules of MMA, clarified the background on how the rules for female were adopted and their purposes through surveys of those who were involved in establishing the rules, and verified the validity of adopting rules that differentiate between the genders. Through an analysis of the results, it became clear that different rules by gender were adopted based on the following considerations: (1) the skill level needed to overcome the danger; and (2) physical and social disadvantages that women suffer as a result of injuries. Nonetheless, there is no denying the existence of a certain gender bias when there is an assumption that women suffer more social disadvantage than men as a result of facial injuries. The fact is, however, that these disadvantages are recognized in courts cases and other situations, and event organizers and rule developers have no choice but to take them into consideration.
