The best-selling novel The Da Vinci Code has seriously damaged people's faith in the Christian Church, a survey has found.Two thirds of Britons who have read Dan Brown's thriller believe that Jesus fathered a child with Mary Magdalene, a claim rejected as baseless by historians and Bible scholars. Those who have read it are also four times as likely to think that the conservative Roman Catholic organisation Opus Dei, whose members include the Cabinet minister Ruth Kelly, is a murderous sect. Seventeen per cent of readers are convinced that the lay group, whose founder was canonised by the late Pope...