UNITED NATIONS — Nearly a quarter of U.N. member states are urging that the next secretary-general, for the first time, be a woman. It’s the latest sign of momentum for the idea as campaigning to succeed Ban Ki-moon at the end of 2016 begins in earnest. A document obtained by The Associated Press points out that in the 70 years of the world body’s existence, “a female candidate has never been openly considered.” Forty-two countries have signed on to declare that “the time has come for a woman to hold the highest position.” The new Group of Friends in Favor of a Woman for Secretary-General of the United Nations includes two of the largest contributors to the U.N.