David James Purslove Barker (29 June 1938 - 27 August 2013) was an English physician and epidemiologist and originator of the Barker Hypothesis that foetal and early infant conditions have a permanent conditioning effect on the body's metabolism and chronic conditions later in life.

He was born in London the son of Hugh Barker, an engineer, and Joye, a concert cellist. At Oundle School, he developed an interest in Natural History and was given special