His mother, Edith Cockcroft, was also a teacher. Arthur was the oldest of his parents' three children, all boys, all of whom became scientists.
Kanyang ina, Edith Cockcroft, ay din ng isang guro. Arthur ay ang pinakalumang ng kanyang mga magulang 'tatlong mga bata, lahat ng mga Boys, lahat ng mga sinugo ay naging siyentipiko.