I suppose compared to other game systems it could seem like more of a chick system. It seems it is geared towards a more feminine audience, with their bright colors and their lack of gorey accessories. There are far fewer games with blood, guts, and nudity than some other systems offer.
What is far more likely is that it is geared towards a more specific audience. One that prefers less violence. They have quite a few simulation and puzzle games. Many of their action games are not shooter and many use "cuter" characters. There are a great amount of "female" games mixed in as well.
Despite this, I don't think it is a chick system. Let's take a look at the facts:
-They're more brightly colored
-Not focused on blood, guts, gore and nudity
-Cute characters
-Simulation and puzzle games (aka brain games)
-Many "girl" games
At first glance would one think feminine? Perhaps, but take note that this system came out around 2004. The 3DS released around 2011. Considering these facts, I think it was aimed not at a female audience, but rather at a younger audience. For children, there is a much clearer distinction between "girl" and "boy" things, which seems very clear with the DS games. There are animal and barbie (girl) games and there are lego and superhero (boy) games. There are fewer gender neutral games in compared to the many games other consoles have. In my opinion, it was aimed to be more of a child's system rather than a female's system. Not to mention that adults playing games wasn't nearly as acceptable back then as it is now, so many more games were aimed at younger audiences and many games were bought for children.
Also, as a side note. Even if it was trying to be a "chick" system, from what I've seen most women prefer the "guy" games so it would have been quite ineffective.