Roy Harfitt was born in Alexandria, Egypt on 15 March 1944. He had no medical connections. His grandfather, Vicar of St Mary at Hill (the Billingsgate fish market church) founded the Christian Evidence Society. Ronald Stanley Harfitt, his father, worked in civil aviation and his mother was Josephine

David Stewart was an ophthalmic surgeon at Freemantle Hospital, Western Australia. He was born in Perth, Western Australia on 5 June 1942. His father, Andrew Malcolm Stewart, was an agricultural scientist at the University of Western Australia and a grazier; his mother, Halsted Noël Stewart née Whit