Do you want teenaged males, ages 13-19? Get some teenaged females, ages 13-19
I think that is THE key marketing point. As we know, the majority of players (or at least roughly 50%) in LARPs are females. In addition, most new role-players tend to gravitate towards LARPing, rather than pen-and-paper RPGs -- few of them have even heard of them.
IIRC, Fine assumed that the traditional RPGs (D&D, especially) deal too strongly with themes of violence and sex (especially abusing female NPCs; however, unless I'm completely mistaken Fine researched gamers back in 1983 when this probably WAS a real issue) to female tastes. Also, he concluded that most female gamers become gamers via their boyfriends, and gaming is something they must do if they don't want to spend their weekends alone. Also, he stated that RPGs are perceived as a male-dominant hobby as it is based on another male-dominant hobby: wargames. As such, girls don't naturally start gaming; they prefer riding or ballet (for example) because that's what other girls (especially their friends) do.
Gary Gygax, on the other hand, estimated in 1978 that roughly around 10-15% of people who play D&D are female. This seems to be a pretty reliable number, I think. Females comprised 19% of the people who took the WoTC survey in 1999, and a similar survey conducted by Kittock in 2001 (this was an internet survey open to anyone) showed that 9% out of people who replied were female.
Anyway, I think it's just as important to market RPGs to females as it is to kids; there're probably a lot of potential gamers in female cosplayers, anime/manga fans, fantasy/scifi fans, computer game fans. The problem is... publishers don't usually market the game outside the hobby circles. LARPing, on the other hand, is much more visible in mass media than pen-and-paper RPGs. In addition, RPGs are published by RPG publishers, so outside of CONs, they are more or less "invisible" to potential female gamers. Also, while I wouldn't necessarily see any "stigmata" associated with RPGs, they *DO* look pretty obscure and esoteric to non-gamers, and role-playing is pretty hard to explain so that it sounds appealing to "mundanes". Finally, RPGs may require a lot of dedication, time and effort, so they're not exactly suitable for "passive consumption".