Anyone who has read more than a few chapters of Hunger Games will pick on one fact quickly, Katniss is not your average "damsel in distress" female character. In fact, she seems to take on some almost masculine qualities through her actions in the books. So why is this? Katniss is beautiful, she has relationships with men, and she has many physically feminine qualities. So why then does Katniss get labeled as masculine by readers, and so quickly? The answer is that Katniss challenges gender relations by taking on the role of fighter or protector, while allowing Peeta to take on the role of nurturer.
Within our society we have learned certain social expectations for each gender, and therefore have associated different roles with femininity or masculinity. In Western cultures, women are seen as softer, more gentle people, therefore being given the roles of nurturer. Men are in turn seen as the strong, more emotionally stable ones, and in turn as generally expected to be the protector, the bread winner, and the fighter. As much as many people may reject these roles and choose to pursue paths outside of gender stereotypes, there remains an almost universal knowledge of their resistance. This is what makes Katniss stand out so much, especially with Peeta present as a foil to her.
Even before the games start, Katniss presents a masculine air by acting as the provider for her family through hunting. At this point though Gale is still there to prevent a very stereotypically "manly" image, which makes Katniss's actions less noticable. Once entering the games, Katniss immediately goes into survival mode, hunting, killing, fighting, and ruthlessly surviving. When Peeta is injured, Katniss is hopeless at the feminine aspects of caring for him, such as medicine, but excells in the physical protection. She shows a violence, and a willingness to fight which is seen as very masculine.
Peeta acts as an excellent contrast to Katniss, as he has almost the exact opposite characteristics. His feminine actions begin with his sacrificing himself for Katniss, as the act of self sacrifice in a non-combative situation is generally considered a female quality. Once in the cave, Peeta begins to rely on Katniss for everything from food, to shelter, to actual protection from enemies. His passivity, and reliance upon another cast him in a very feminine light. Essentially, Peeta and Katniss have switched traditional gender roles. The Hunger Games still contains the usual boy saves girl and then they fall in love motif, it simply changes it to girl saves boy. The series does not break any new ground as far as the development of romance, it simply switches up the genders, and in doing so questions the whole system of gender relations.