Wired.com talks about how Japan's game makers are now in the grip of girl fever - scrambling to market directly to women gamers who were once ignored. The success of the Nintendo DS seems to be the main reason, with many of the 16 million sold in Japan so far, having been snapped up by females thanks to games like Nintendogs and Brain Age.
In fact with the upcoming Mother's Day, Nintendo is advertising hard trying to get children to buy their mothers DS's. The article also talks about how there seems to be a general acceptance of female gaming, with it looking more stylish than it used to. Although there are games popular with both men and women, such as New Super Mario Bros. and Final Fantasy III, more and more games are being made specifically for the female audience or taking them into consideration.
On the subway the DS rules whereas the PSP just doesn't seem to appeal to women, with none of them seen playing with one. They are instead regarded as being for "hardcore" gamers and are less accessible compared to the DS thanks with its simple input methods and unique software.