For centuries the Dukedom and Duchy of Cornwall has been the title and source of income for the eldest son of the Monarch. And now, even after succession laws have changed to allow females equal rights to become Monarch, the Duchy will not be inherited by the eldest child of the Duke and Duchess of Cambridge if the child is a girl.
Prince Charles as eldest son of the Monarch is the current Duke of Cornwall.
The title of Duke of Cornwall is automatically taken by the eldest son of the Monarch along with that of Duke of Rothesay in Scotland. It has with it a Duchy which contains a vast portfolio of property and land which the eldest son (currently Prince Charles) uses as their source of income.
There was initially an amendment made in the Succession to the Crown act when it was in Parliament a few months ago, but it was withdrawn as it wasn’t ‘specifically within the mandate of the bill’.
This now means that should the Duchess of Cambridge give birth to a baby girl, but later have a boy, the boy will get the title of Duke of Cornwall unless a change in the law is made.
The revenue from the Duchy will, however, still be given to the eldest child through a special arrangement and the title of Prince (or Princess) of Wales is something which the Monarch issues and can be irrespective of gender.
Once Prince Charles accedes to the throne, Prince William will automatically assume the title of Duke of Cornwall (becoming the Duke of Cornwall and Cambridge) and it would be up to the King whether he would get the title of Prince of Wales (his wife becoming the Duchess of Cornwall and Cambridge and Princess of Wales respectively).
The royal baby will be Prince or Princess <NAME> of Cambridge at birth and could later be Prince/Princess <NAME> of Cornwall & Cambridge or of Wales.
Fortunately, a private member’s bill has been started in the House of Lords by Lord Lucas which would see that the eldest child of the Monarch, regardless of gender, would become Duke (or Duchess) or Cornwall. Tory MP Mary Macleod has tabled a Ten-Minute Rule bill in the Commons on the issue.