PROFESSOR John Marshall, one of the original members of the Pontifical Commission on Birth Control, died last weekend at the age of 91. He was one of six people – three laymen and three clerics – appointed to the commission, set up by Pope John XXIII and later enlarged by Pope Paul VI.The professor emeritus of clinical neurology at the University of London had been appointed in part because he had carried out extensive research on natural family planning. In an article for The Tablet, Professor Marshall said he started his time on the commission viewing the use of artificial ­contraception as “intrinsically evil” but ­gradually shifted to believing that the church ban on artificial birth control could not be upheld. His grandson, David Geiringer, is continu