Charlotte became the first female royal to benefit from The Succession to the Crown Act (2013), which states that girls will not be overtaken by younger brothers.
While Charlotte has retained her place as third-in-line to the throne in front of Louis, other female royals missed out on the change, as the Act only applies to those born after October 28, 2011.
The late Queen and Duke of Edinburgh’s only daughter Princess Anne is much further down the line of succession than her younger brothers Prince Andrew and Prince Edward.
The Princess Royal, who celebrated her 72nd birthday in August, is currently in 16th place behind her niece Lady Louise Windsor.
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If the rules had been changed at the time of Anne’s birth in 1950, her children Peter Phillips and Zara Tindall would be much closer to the throne than their cousins Princess Beatrice and Princess Eugenie, who are currently 10th and 11th.
At the time of her birth in 1950, Anne was third in line to the throne as the second child of then-Princess Elizabeth.
She moved to second in line when the Queen ascended the throne, but the birth of her brothers Prince Andrew and Prince Edward in the 1960s saw her position drop to fourth.
When Andrew and Edward welcomed their own children, Anne’s position in the line of succession only dropped further, and she now stands in 16th.
Meanwhile, in Spain and Monaco, males take precedence over females. For example, Prince Albert of Monaco and Princess Charlene’s eight-year-old son Prince Jacques is the heir apparent, despite being two minutes younger than his twin sister, Princess Gabriella, also eight.
Princess Charlotte will likely also receive a prestigious title later in life – due to her being William’s eldest daughter.
Royal expert and author of Prince Harry: The Inside Story, Duncan Larcombe, said: “The title of Princess Royal is traditionally bestowed on the eldest daughter of the monarch. It is a title that remains for life, so Princess Charlotte will have to wait at least until the death of the current Princess Royal.”
Mr Larcombe added: “Princess Anne had to wait until 1987 before her mother the Queen bestowed the title of Princess Royal on her, even though the title had been vacant since 1965.”