Diagram, graph of mother's age against father's age by Francis Galton A graph of 'Mother's age' plotted against 'Father's age' with birth rates labelled on the results. Includes notes to the illustrator. Subject: Statistics A print of this diagram was published in volume 55 of the Proceedings of the Royal Society alongside the paper 'Results derived from the natality table of Kõrösi by employing the method of contours or isogens'. 1894