Another boomerang kid story-- this one notes up high the impact of "economic necessity," student loans and credit card debt (with an old 2002 stat; the latest number is lower).
But personal finance experts can't agree: are you really helping your offspring in the long run? What about your own retirement?
This is my own personal biased opinion: I think living at home is OK if the younger person has a plan, because it is self-limiting; annoying for both sides. Paying rent so they can live in the city is not. It creates a false sense of independence, removing the incentive to save or budget (not to mention it ruins neighborhoods now full of trust fund kids). My first year out of college, my parents paid for, not my rent, but my health insurance. That was really looking out for me.