A century old ruling by King George V in 1917 stipulated that the heir to the throne's son would become a prince, but a daughter would not become a princess, instead she would be bestowed the title of Lady.
The Queen felt that “it was time such a long-standing imbalance was formally rectified,” the Mail Online reported.
The proclamation was issued through the House of Lords on December 31, 2012 and reads: “The Queen has been pleased by Letters Patent under the Great Seal of the Realm dated 31 December 2012 to declare that all the children of the eldest son of The Prince of Wales should have and enjoy the style, title and attribute of Royal Highness with the titular dignity of Prince or Princess prefixed to their Christian names or with such other titles of honour.”
Kate was afforded the title Duchess of Cambridge when she wed William in 2011, and when he becomes the King of England she will become the Queen.
A new Succession to the Crown Bill was enacted in late 2012 which said that regardless of the sex of the child the first born will become the monarch.