Gaming is traditionally heavily associated with males, but a lot of girls nowadays get into gaming, perhaps not always at the same serious level as males, but it is becoming more widespread.
Girls probably don't actively seek out video games, but rather video games find them. I was responsible for getting my sister into games. At a young age, I got a Nintendo 64, Nintendo Gameboy and a Playstation. As my only sibling and my parents making me babysit her (I'm 10 years older than her), she was a perfect companion to play games with, although she was quite terrible at the game initially, she eventually got the gist of things and actually become a worth member of the team in the game.
I think that girls themselves won't invest in a gaming machine such as a Playstation on their own, but if a member of the family such as an older/younger brother or dad who buys such a device will eventually lead them to participate in games and in some cases, take them even further and play professionally in teams. But the main point here is that a 'push' of some sort is usually necessary to get the girl into gaming. It may not necessarily be from a male in the family, some might start gaming when they get a particularly good game as a present.
With the rise of the Internet also, gaming has also become a lot more accessible in the sense that a home PC (or Mac) and an Internet connection is all that is needed to get into gaming. And with so many people on social networking sites nowadays, it doesn't necessarily have to be just a male in the family who has influence, but male friends online. In this instance I'm not so much talking about the big name games that show up at E3 conventions, but rather browser based games such as the third party Facebook applications. Which have a social element to it which appeals to girls
