Why Smother Mothers Welcome Boomerang Sons Back

Reuters recently published results of a study on "Flying the Nest" that showed how "smother mothers" (overprotective moms) welcomed their adult "boomerang sons" back home. Why are do women let adult sons live at home? Is it healthy?

The 2010 film "Cyrus" explores the humor and pathos of smother mother love. The tagline says is well: "A recently divorced guy meets the woman of his dreams. Then he meets her son." Bouncing off from this film and the debate over boomerang sons, why are mothers quick to let adults sons live at home, while adult daughters fly the nest for good?  Why Smother Mothers Welcome Boomerang Sons Back