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In this photo released by United Nations Population Fund, Gamze Ozkan, 18, holds her new born baby boy, Yusuf Efe, at the Zekai Tahir Burak maternity hospital in Ankara, Turkey, early Monday, Oct. 31, 2011. According to the U.N. Population Fund, Yufuf Efe, son of the unemployed mother and a worker husband, will be one of 7 billion people sharing Earth's land and resources by Monday. (AP Photo/Nezih Tavlas, UNPF) EDITORIAL USE ONLY

'7 billionth' babies celebrated worldwide

The U.N. chose October 31 to mark the world's population reaching 7 billion with a string of festivities worldwide, and a series of symbolic 7-billionth babies being born.