Bill MacGregor was born in Melbourne, the only son of William MacGregor, a surgeon and farmer, and his wife, Mary Gladys. He was educated at Geelong College before entering Melbourne University for his medical training. After qualifying in 1943 he served in the Royal Australian Air Force Medical Service between 1945 and 1947. He soon decided to pursue a career in obstetrics and gynaecology, and moved to England in 1949 as a registrar in Oxford. He was appointed a senior registrar in Bristol in 1952 and a senior lecturer at University College Hospital in London in 1956, where he was influenced by Professors Browne and Nixon. He became a reader in obstetrics and gynaecology in the University of London at the Hammersmith Hospital, where he developed his interest in gynaecological oncology and was influenced by Ronald Raven and Sir John Stallworthy. He became a Fellow of the Royal College of Obstetricians and Gynaecologists in 1961 and gained a reputation for teaching, which he enjoyed. He travelled widely, but also retained his sporting abilities which included golf, tennis and water skiing. During his training period he wrote articles on cardiac output during pregnancy and the 'unstable lie of the foetus'. He had two sons and one daughter from his first marriage to Elizabeth Mary Kenny in 1943; and three sons, William, Robert and Angus, and two daughters, Helen and Alison, from his second marriage to June Patricia Lawson in 1956. He died on 18 December 1992.