Britain's Prince William and the Duchess of Cambridge's next child will have an equal shot at ascending to the throne, regardless of whether it is a boy or a girl, thanks to a law put in place by the country's parliament in 2013.
The Succession of the Crown Act is designed to replace the 1701's Act of Settlement, which declared that men could succeed an older sister's place in the line of royal succession, in a custom known as male primogeniture.
According to Little Things, this law would have prevented the current Queen Elizabeth II from ever holding the throne had her younger sister, Princess Margaret, been born a boy.
The new law was rushed through Parliament before the birth of William and Catherine's first child, George, in 2013 and went into effect two months before the birth of their second child, Charlotte, in 2015, the BBC reports.
Seniority still reigns supreme in the laws of succession, so Charlotte is still outranked by three older men. However, she still does rank above her uncle, Prince Harry, and her granduncle Prince Andrew, who at one time held much higher positions in the successional line.
Queen Elizabeth, 91, has ruled for 65 years. After she dies, the crown will go to her son, Prince Charles, who at age 68 is likely not to take his mother's record as the Britain's longest-ruling monarch, according to Newsweek.
After Charles, the crown will pass to his and Princess Diana's first son, Prince William, 35. Although she gave birth to William's heirs, Catherine, Duchess of Cambridge, holds no position in the royal line.
Barring any accident or illness, 4-year-old George will become king after William. Charlotte would only become queen if she outlives George before he has children.
If George grows up to have children, they will outrank Charlotte as being next in line for the throne. George's first-born child will retain the highest ranking over his or her younger siblings, regardless of whether they are boys or girls. By the same logic, a second-born female child would also retain their ranking over any subsequent children, regardless of gender.
In addition to revamping the succession rules, the BBC reports that the Succession of the Crown Act made it so that heirs who are later than sixth in line can marry without the queen or king's permission. It also allows members of the Royal Family to marry Roman Catholics without giving up their place in line, but Roman Catholics are still not allowed to be the country's monarch. Britain's monarch is also the head of the Church of England, the country's state church.