His parents (mother was a physician; father was a chemist) wrote a letter to the British Medical Journal arguing that spinach is harmful to children because it contains oxalic acid, which eats the calcium needed to grow strong bones and teeth. The letter - a response to a Journal article which stated "spinach would seem to be particularly valuable for the nutrition of children, provided they can be persuaded to acquire a liking for its somewhat bitter taste" - got a write-up in the 30 March 1953 issue of Time magazine.