i'm andrea mccarren in baltimore.r questions answered by the john hopkins center for gun policy and research coming up. intlz we continue our coverage -- >>> we continue our coverage of the tragedy in connecticut and how it could possibly change our gun laws with the slaughter of 20 children the tipping point. andrea mccarren looked at a body that studies gun violence from a public health perspective. >> a nonpartisan research center, bruce. this may be the tipping point like you and i were discussing. consider there. there are an estimated 280 million guns in the hands of private citizens right now. that's one for every man, woman and child in this country. we use social media to solicit your questions and here's what we found. >> i do think that this connecticut shooting might represent a real game change. >> reporter: one question you had, why is it so hard for the u.s. to enact policies like in the u.k. that have reduced mass shootings. what actions can be taken? >> households that have both guns and young childre