A difficult and layered question, which I would prefer to answer in the sub-sections which I have noticed in the question and the discussion thread.
First, the question as to whether Tabletop RPGs are more unpopular amongst women than amongst society in general.
Gaming in general is considered by society as a whole as being more of a masculine hobby than a feminine one. It's also an unpopular niche hobby, even despite the recent boom in fantasy, sci-fi and modern horror in other media making the subject matter of the typical game rather more acceptable than perhaps it used to be.
The longstanding feminist gripe about the stereotypical Vallejo-esque chainmail bikini-clad female as an objectification of women can now reasonably be countered by reference to all the shirtless beefcake to be found in recent fantasy films (Prince of Persia), TV series (True Blood, Heroes) etc. not to mention the tendency of Edward Cullen to get semi-naked at any opportunity during that abysmal franchise. Fantasy characters as sexualised fantasies are now fair game for any gender and any orientation.
What may take longer to destroy is the perception of RPGers as unwashed, unshaven, physically unfit and enormously socially awkward male nerds. But this is very much a chicken-and-egg situation. When RPG/Hobby stores start being well-lit comfortable places full of beautiful people of both genders, that will become the norm.
Assuming that the "girls" of whom you speak are reasonably open-minded and prepared to have some unselfconscious fun, the only things that should put them off are the possible misbehaviour or sexist reactions of the other players, either directly (openly staring at breasts and making innuendos like they were channeling the ghost of Sid James) or through their PC proxies (the old "CHA check to seduce" chestnut).
A good GM should stop both of these before they even start, by verbally putting players in check if they say something out of line in person, or forcing them (for instance) to ROLEPLAY the infamous seduction attempt (that is what we call our fine hobby, after all) and watch them squirm.
Second, whether Tabletop is more or less popular than LARP amongst women.
I think that girls and guys may play games for different (although somewhat overlapping) reasons, which seems to inform the "D&D for the Boys, WoD for the Girls" sub-argument which is iterated in this thread.
A study into computer gaming in the 90s found that women and girls wanted more games which offered socially interactive choices, whereas guys tended to go for the more violent titles. This is of course a massive generalisation, but the ability to beat/shoot/nuke/burn/stab up stuff without needing the physical prowess to do so IRL is a key draw to many gamers, especially, but by no means exclusively young male gamers.
This is traditionally a strong part of D&D, with its lineage of combat simulation (remember that it came from a swords and sorcery war-game called Chainmail and was designed by a company called Tactical Studies Rules).
Conversely, LARP (or at least, the type of LARP which isn't decided with the business end of a boffer weapon) tends to involve free-form social simulations.
In my personal experience? Mixed RPG groups work well for the same reason that mixed social groups do. All male groups are often slightly scary, socially retarded and can turn into silverback city pretty fast. All female groups have their own drawbacks, often involving extreme cattiness. I should for the sake of balance mention that only get to observe this in social situations when my Anthropologist training kicks in and when, David Attenborough-like, I sit silently in the periphery, my presence forgotten by the observed. Therefore I've never seen what an all-female RPG group looks like.
As a GM I want a story with a mixture of play types to cater for the different needs of your group, otherwise some feel left out and the story is 2D and shallow (like a bad action film) or verbose and boring (like bad chick lit/ Stephenie Meyer novels).
I have played (but mostly GM'd) AD&D, Shadowrun, Rifts, WoD, Fading Suns and more others than I can be bothered to list here and to be honest I tended to gear things to my audience as much as possible.
Being a teenage boy at a mostly single-sex school when I started, this was principally hack-n-slash with a plot and some conversation added for the sake of completeness, continuity and rationality.
Between school and university I lived in Italy for a year (having finished school at 17 like the precocious little shit I was, I wanted to work, learn another language and generally blow off some steam before I was of legal drinking age in the UK) and after about 5 months I found a mixed-gender group of Italian gamers, which was a massive eye-opener. I played alongside men and women, massively stretching my language skills by trying to follow the plot and dialogue which they wove into the sessions.
Returning to England for Uni and checking out the Adventure Gaming Society was a huge disappointment. 90% were male. 90% of these were beardy-weirdy proto-dwarf types. The kicker was when Friday & Saturday nights turned out to be the most popular nights for games. Realising that I had come to University to learn some things which couldn't be learnt from books, I fled to spare my social life, only braving the game shops in town (staffed by a real-life British Weird Pete) to buy KoDT and some books which would sit read but unplayed in my student hovel whilst I dabbled in mind-altering substances, casual sex and varsity sports.
I know that not everyone has the same experience- my oldest friend (and oft-time gaming partner) recently married a girl who he met through the society at his university (notably their gaming group is roughly 50-50 mix) and I have had the pleasure of join their group for a game of 7th Sea (ridiculous accent at the ready) before acting as the best man at a wedding which, due to the date (17th September) had a distinctly "Pirate" theme.
I suppose the message I'm trying to relate is that stereotypes can become a self-fulfilling prophecy unless everyone works to undermine them.
