Bernanke: Housing woes may last

WASHINGTON (Reuters) -- Federal Reserve Chairman Ben Bernanke has told Congress the U.S. economy will grow gradually this year and gain steam in 2008, but warned there are many risks to the outlook and stressed the U.S. central bank is on guard against inflation. --- But Bernanke warned that a slowdown in the U.S. housing market may last longer than anticipated, and said that further hikes in energy and commodity prices could spark inflation and push closely watched core inflation up.