It's hard to laugh about religion in Northern Ireland, but Oxford theologian Alister McGrath likes to tell the following joke that hints at the challenges he faced as a young skeptic in that troubled land. While visiting Belfast, an Englishman was cornered by three thugs. The leader asked one question: "Are you a Protestant or are you a Catholic?" After a diplomatic pause, the Englishman said: "I am an atheist." Confused, his attacker asked: "Are you a Protestant atheist or a Catholic atheist?" The tough religion questions continued when McGrath entered Oxford University, where he became the rare student who traded his Marxist atheism for Christianity while studying science. He would eventually earn two doctorates -- in molecular biology and theology. Today, McGrath teaches at his alma mater and is admired by academic leaders around the world who are tired of being cornered and asked: Are you a Christian or are you an intellectual?