Christian kids are typically sent to Sunday school for lessons on the Bible and morals. For nonbelievers, there's atheist Sunday school. With an estimated 14 percent of Americans professing to have no religion, according to the Institute for Humanist Studies, some are choosing to send their children to classes that teach ethics without religious belief. Bri Kneisley sent her 10-year-old son, Damian, to Camp Quest Ohio this past summer after a neighbor had shown him the Bible. "Damian was quite certain this guy was right and was telling him this amazing truth that I had never shared," said Kneisley, who...