because Im afraid of emasculation, both symbolic and literal. first of all, it sucks to get beat by a girl, its just not supposed to happen. Its embarrasing. And second, what if while ur playing a girl she hits you in your balls. its happened to me more than once. the most recent was a couple months ago in a pe soccer game. she blasted me. ever since then, ive been reluctant to play sports with girls. im just afraid im gonna get an "accidental" knee in my balls