According to the Reddit blog, they just changed the default subreddits, adding /r/TwoXChromosomes. Since it has barely any subscribers compared to popular subreddits (the old standard way of becoming a default was based on subscriber count), I can only assume it was handpicked by the admins to indoctrinate new Redditors with feminism and attract more women to the site.
Do you see trouble brewing? Is Reddit turning into Tumblr? And if so, should TRP have a lifeboat on another site that we can turn to when this sub is eventually taken down?
EDIT: Welcome, downvote brigade. Stay classy, Reddit.