I'll preface this by saying that, for all intents and purposes in this article, I shouldn't be considered a female gamer despite meeting the requirements. I'm closer to your typical male mentality than I think the usual female gamers are, and so I'll make sure not to speak for the general purposes. That, and I've never played an MMORPG, because I dislike the idea of cooperating and depending on others to do my grindy RPG tasks. I don't like FPSes in general, so with both of these out, I haven't been subjected to the kind of horror story others have found themselves with, from "Tits or GTFO" to misogynistic comments about going into the kitchen for a sandwich that the juvenile teabagging griefers love so.
A friend of mine recently linked me to this article, with the research they referenced sadly not being available without at least registering, and I'm not interested enough to do that. The article mentions a "changing demographic", which I will politely guess is pure bullshit. Show me someone who has not heard of Mario, Sonic, Zelda, Final Fantasy or Mega Man in their childhood, and I will point out that it's not due to their absence or presence of external genitals. I'll even venture that what they liked then and like now is pretty similar, and just a consequence of the evolution and creation of the myriad of new videogame genres more so than any shift in women's preference about what they play.
There were as many female gamers then as there are now, they just weren't as well-known or vocal. The NES was marketed as a family entertainment system, not as a toy for little boys. Despite all the games based on shows for boys, and the Zapper being bundled with a hunting/shooting game, parents didn't frown up their precious princess playing boys' games. In fact, I'll have to retract my claim to being an "outsider" for a second to say that I, an only female child, was blessed with an NES once it became cheap and right as the SNES's era began.
And before there was the NES, there were home computers, edutainment games not marketed at a particular gender, arcade games like Pacman--which was actually designed to appeal to women by being less violence-oriented than its contemporaries!--and early western computer RPGs such as Alakabeth, A.K.A. "Ultima 0", which also didn't target any particular gender.
The ScienceFiction.com article continues by saying that despite female gamers being half of the market share, marketing efforts have ignored the group. Is it because they don't want to cater to the "fairer sex", or just because they've finally realized that their efforts to make "girl games" is extremely offensive and only created spectacular shitfests such as unplayable Barbie messes made from cotton-candy pink pixels and the most vapid stories they could think of to "appeal" to girls?
Female gamers buy the same games male gamers do. Whatever you have in your pants doesn't keep you from appreciating a story or the gameplay, or make you hate it. Despite different hormones, attitudes and behaviors, male and female gamers have common ground in gaming. Female gamers wouldn't have made half of the gaming population if they didn't appreciate games, so somewhere along the way, despite "male-oriented" game development, the games produced must have been diverse enough to have attracted as many women as there are men!
All I can find on differences between men and women seems to be that female gamers form more of an attachment to the player avatar or character, to the point of seeing death more harshly, and that as a whole they're not as violent. That's a given if you look at the psychological differences between the sexes, however, and makes sense from the evolutionary standpoint where men evolved as hunters and women as nurturers. The SF.com article, once again, says that females are "much more likely" to solo than males, but an article dating back from 2009 says the difference isn't quite so drastic, with 20% of females and 24% of males playing solo due to various restrictions, and only 6.6% of females preferring to play alone with 5.3% amongst males.
I'll liken this to the rapidly closing cultural gap between American and Japanese gamers. For years, due to cultural differences, game developers thought that Japanese games wouldn't sell well in America. And yet today, we see developers turning international, and programmers creating games to cater to both Japanese and American gamers because it turned out they had a pretty large common ground to build on despite the original rift.
All I can hope is that the developers, designers and programmers discover this quickly, and then add a bit more of a feminine touch to their games so that the females are more consistently written as tri-dimensional characters as opposed to half-naked, titillatingly clad pieces of meat with jiggle physics for pubescent boys and immature frustrated men to masturbate over like HD porn.