Prince George, five, is the oldest of Prince William, 36, and Kate Middleton’s, 36, children.
Princess Charlotte, 3, and Prince Louis, five months, are all next in line to the throne behind their brother.
However, they are currently known as Prince and Princesses, not Dukes or Duchesses like their parents.
When do Royal Family members gain a dukedom or any other titles?
Members of the Royal Family often become Dukes when they get married.
Prince William became Duke of Cambridge when he married Kate in 2011, who also then became Duchess of Cambridge.
Similarly, Prince Harry and Meghan Markle became the Duke and Duchess of Sussex upon their marriage earlier this year.
Therefore it is likely that Prince George will remain a Duke until he marries his partner in the future, as well as Prince Louis.
When it comes to which dukedoms are available, there are a number that could be bestowed to the royal children.
Charles Kidd, editor of Debrett’s Peerage & Baronetage told the Telegraph: “The dukedoms of Cumberland, Albany and Teviotdale are all suspended, meaning there could be claims to those titles.”
Prince George is unlikely to take his father’s title when he becomes King.
Prince William, however, could become Prince of Wales when Prince Charles takes the throne.
Queen Elizabeth was the Duchess of Edinburgh when she married Prince Philip, which will be passed onto her son Prince Edward’s wife in the future.
Currently the Countess of Wessex, she will gain the title when Prince Edward becomes the Duke of Edinburgh, taken from his father.
However, Princess Anne is not a duchess and is Princess Royal – something often given to the eldest daughter of the reigning monarch.
However, only one can be Princess Royal so Princess Charlotte could inherit this title in the future.
The Queen was unable to take the title as her aunt, Princess Mary, held it until her death in 1965.
A Duchess is higher than a Princess Royal so it could be decided to make Princess Charlotte a Duchess in line with her brothers.
Royal historian Marlene Koenig said: “Now with gender equal succession, I think it would be more possible to grant a peerage to Charlotte. Prince Louis will get one when he marries, so it would only be fair if Charlotte was named a Duchess on her wedding day.”
