U.S. House Democratic Leader Nancy Pelosi has called for an ethics committee investigation of Representative David Wu.

A newspaper had reported allegations by a young woman of “aggressive and unwanted sexual behavior” by the congressman after last year's election.

This is the second time Wu has faced accusations of unacceptable sexual behavior. In 1976 Wu was accused of rape by a former girlfriend, but no criminal charges were filed. And shortly before the 2010 congressional elections Wu engaged in erratic behavior that led several staff members and consultants to quit his campaign.

Staffers for Wu, a Democratic representative from the western U.S. state of Oregon, say he will not resign. There are reports that Wu will not seek reelection in 2012.

Representative Wu is the only member of Congress born in Taiwan and the first Chinese-American to serve in the U.S. House of Representatives.