A law from the 18th century which could see a daughter born to Prince William and Kate Middleton unable to become Queen is being challenged.
Male Royal heirs currently have prior claim to the British crown over their older sisters under the 1701 Act of Settlement.
Labour backbencher Keith Vaz, is seeking to legislate the removal of gender in determining the royal succession.
"With the marriage of Prince William and Catherine Middleton, we have a once in a generation opportunity to change the law," said Vaz.
"Prince William looks like a very modern prince. If he has a daughter first, it is only right that she become Queen of England," he added.
The couple are due to marry in London's Westminster Abbey on April 29.
Prince William, 28, is the eldest son of heir-to-the-throne Prince Charles and the late Princess Diana. As such, William is second-in-line to the crown held by his grandmother Queen Elizabeth.
The incoming coalition government has shown little enthusiasm for change, not least because it requires the agreement of 15 independent British Commonwealth countries which share Queen Elizabeth as their sovereign.