The break-up of the family unit, two-income households, missing baby-daddies, and now social media. Social norms have been challenged aggressively since the flower children of the 60's. Mix it all together and you get Chit-Salad.
This is part of it, but I think there has been an organized, concerted effort by the Left to destroy societal norms so that they can rebuild the society in the leftist mold. This effort has been going on for a long time, just read The Communist Manifesto, which was written in the mid 19th century. This effort picked up steam in the US in the 1960's and has been under way ever since.
