Even if Prince Williams and his wife Kate Middleton's first-born baby is not a boy, she will still be recognized as the first female heir to succeed the British throne.

A great change in the law gives female heirs equal rights to their male counterparts to the throne, where the first-born boy used to take precedence to prevent a return of a Catholic monarchy.

The Sovereign Grant Bill, which renews the way the royal family is funded, was passed by the House of Lords last week and is now set to be law.

Clause nine states that any heir to the throne, who is not the Duke of Cornwall, can receive revenues from the Duchy of Cornwall. It means that the first-born baby of Prince Williams and Middleton, whether girl or boy, will inherit one of Britain's wealthiest estates: Duchy of Cornwall valued at £700 million.

The principle that should run through all these issues is that men and women are treated equally, a constitutional expert Lord St John-Stevas told the Sunday Express.

Many attempts have been made to revise the 1701 Act of Settlement since 1981, but all came to nothing devoid of government support.

After William was engaged to Kate Middleton in Nov. 2010, the demand for change in law was brought to attention.

The Duchy of Cornwall covers about 54,000 hectares of land in 23 counties, chiefly across southwest England and it provides almost £18 million per year to Prince Charles, the Prince of Wales and Duke of Cornwall.