Some Christian denominations around the U.S. have been slowly warming to the idea of gay marriage. A few have even made an about-face. Not so with the country's largest protestant group, Southern Baptists. The Southern Baptist Convention still preaches that marriage can only be between one man and one woman. But some pastors are softening their message. A Change Of ToneThe Southern Baptist Convention held a gathering of pastors at its Nashville headquarters in April. For an organization that has previously used opposition to gay marriage as a rallying point, statements here from church leaders, like Kevin Smith of Kentucky,...