Females have an upper hand due to the fact they are on a game with boys that are you know, getting to that phase ;) I've been in several guilds with female leaders just for fun, SoN being one of them, and all/most of the members are guys hitting on the leader. Pretty funny.
Anyways, no you don't need to be female to lead successfully. Ice Shadows top 5 gang on era for a year before I went inactive and I never faked being female. (if you don't include tranny Thursday's)