President Barack Obama called Thursday for more robust research into youth concussions, saying there remains deep uncertainty over both the scope of the troubling issue and the long-term impacts on young people. ''We want our kids participating in sports,'' Obama said as he opened a daylong summit on concussions at the White House. ''As parents though, we want to keep them safe and that means we have to have better information.'' The summit signaled an effort by Obama to use the power of the presidency to elevate a national conversation over youth concussions. The White House brought together representatives of professional sports leagues, coaches, parents, young athletes, medical professionals and others for the event. More...