WASHINGTON (Reuters) - U.S. Representative Trent Franks said on Thursday he will resign after two former staff members complained about discussions he had with them about efforts to find a surrogate mother.

Franks, an Arizona Republican who has served in Congress since 2003, said he recently learned the House Ethics Committee had opened an investigation of the complaints. "I deeply regret that my discussion of this option and process in the workplace caused distress," he said in a statement.

(Reporting by Eric Beech)