This is at once a response to both the New York Times article which Professor Silliman linked to on 2 January and to Emily Follin's post on the subject.
I've been torn about this issue since I first heard about it. Lego has slowly dug themselves into a hole over the course of the last decade or two, and this new effort of theirs could either make the hole deeper or give them a better shot at climbing out. They've sort of pigeonholed themselves as a boy's toy -- despite their founding proclamation that Legos Are For Everyone -- because they got very few girls in their focus groups because they were perceived as a boy's toy because there were so few girls in their focus groups...a vicious cycle with no visible beginning.
To me, this new line of "girls' Lego," despite enforcing/promoting gender stereotypes, is a well-intentioned attempt to refute the assumption that Legos are for boys. I think that it could be a step in the right direction, though perhaps a poorly-executed step. It could cause problems further down the road if they continue to separately produce products for both genders, rather than gradually merging them in order to return to the universal appeal they once had.
