MB ChB Manch 1963; D(Obst)RCOG 1965; DIH 1969.
Birtwhistle was born in Stockport on 19 December 1939, the son of a pharmacist. After being educated at William Hulme's Grammar School in Manchester and the University of Manchester, Birtwhistle held house positions at MRI and Park Hospital Davyhulme, where he later specialised in obstetrics. He later became a general practitioner in Stretford, Manchester. Birtwhistle was a member of the Society of Occupational Health, Stretford Medical Society and the Medical Ethical Society.