Several babies born today have been deemed the symbolic 7 billionth person — including a little girl named Nargis in Lucknow, India. Here she is with her mother, Vinita. Rajesh Kumar Singh/AP hide caption toggle caption Rajesh Kumar Singh/AP The Two-Way 7 Billion People? Yes, Give Or Take 56 Million October 31, 2011 While the U.N. has declared that the world's population hit 7 billion today, it also concedes there's a 1 to 2 percent margin of error. And that the milestone might have been reached six months ago — or might not happen for another six months.