Charles Gibson has been named the sole anchor of World News Tonight, effective May 29, it was announced Tuesday by ABC News president David Westin. Gibson, who will perform double duty as coanchor of

Good Morning America until the end of June, will replace Elizabeth Vargas, who upon returning from her imminent maternity leave will anchor 20/20 and contribute to prime-time specials. Says Vargas in a statement, "My doctors have asked that I cut back my schedule considerably, and what works best for me and my family is to return to 20/20 as I raise my new baby and young son." The naming of Gibson to World News' anchor chair also affords Vargas' coanchor, Bob Woodruff, time to recover from the injuries he suffered while reporting from Iraq. "All of us look forward to that day [when Woodruff returns]," Westin says. "But it will be on Bob's timetable, not ours."