eMarketer covers two recent studies, saying that casual games make up the most popular genre, and women are the majority of casual gamers. According to a May, 2006 study by AOL, 29% of respondents said that casual games were their favorite genre, with strategy games rating a distant second place at 17%. A survey just released by PopCap says that 76% of casual gamers are female, and 47% are 50-and-older.
But marketers can make numbers mean anything; another way to look at the initial survey is to say that 70% of respondents had a favorite other than casual games. (1% said they weren't sure of a favorite.)
However you interpret these surveys, we like the idea of games reaching a more diverse audience. Only after that happens can games be as culturally significant as books and movies.