Young first met Joan Elizabeth Mary Dunnett in 1927 when he was asked by Geoffrey Miller to come with him when he went to have tea with his cousin Elizabeth. [Perhaps it is worth noting that Elizabeth Mary acquired the extra name of Joan since she was christened on St Joan's day, but she was known as Elizabeth.] Young married Elizabeth on 9 June 1934 and the first two of their six children were born while Young worked at Cambridge.
Young unang matugunan Joan Elizabeth Mary Dunnett sa 1927 kapag siya ay nagtanong sa pamamagitan ng Geoffrey Miller upang sumama sa kaniya kapag siya napunta sa may tsaa sa kanyang pinsan Elizabeth. [Marahil ito ay nagkakahalaga ng pagpuna na Elizabeth Mary nakuha ang mga dagdag na pangalan ng Joan magmula ng siya ay christened sa St Joan ng araw, ngunit siya ay kilala bilang Elizabeth.] Young kasal Elizabeth sa 9 Hunyo 1934 at ang unang dalawang ng kanilang mga anim na bata ay ipinanganak habang Young ay nagtrabaho sa Cambridge.