My honest answer:
Naturally, girls are better at expressing and understanding feelings than boys. (No, I am not saying that girls are better) Thus, I feel that it would be easier for females to roleplay than males, or at least they'd feel more comfortable. Males are more comfortable doing things, not just chatting. If FeralHeart was a game with action, adventure, or even simply some sort of goal or leveling system, I think more males would play. Females, however, are more comfortable chatting and walking around than fighting bad-guys. I'm not saying that all boys like fighting and hate talking, while all girls love talking and hate fighting; I am only saying that the general population (as well as scientific studies) show that girls are more comfortable talking, and boys doing. (Yea, yea, talking is doing something. You know what I mean.)
Or it could be that girls rule and we chased the boys out, either way. ^^