Ronald Bailey covers it:
A study reported in the December 2011 Journal of Personality and Social Psychology found … religious folks believe the godless are about as trustworthy as rapists. "While atheists may see their disbelief as a private matter on a metaphysical issue," explained University of British Columbia psychologist Ara Norenzayan, one of the researchers, "believers may consider atheists’ absence of belief as a public threat to cooperation and honesty." A study published in the April 2006 American Sociological Review found that 48 percent of Americans would disapprove if their children married an atheist, the highest disapproval rating of any named group.
The Dish 