US President Barack Obama (R) holds up a 3-D model of the influenza virus as he talks with Eric Chen, of San Diego, California, during the White House Science Fair at the White House in Washington, DC, May 27, 2014.The White House Science Fair celebrates the student winners of a broad range of science, technology, engineering and math (STEM) competitions from across the country.       AFP PHOTO / Jim WATSON        (Photo credit should read JIM WATSON/AFP via Getty Images)