Who is the heir to the throne of the Queen?

The British monarchy, like many others throughout history, has traditionally followed a line of succession based on primogeniture, meaning the right of the firstborn child to inherit. While rules have evolved, historically, the oldest son took precedence. Think back to the long line of kings and princes. Although laws have changed to allow the firstborn child, regardless of gender, to inherit the throne, the current heir is still determined by the old rules. Queen Elizabeth II's oldest son, Prince Charles, is therefore the heir to the throne. While the oldest daughter might seem like a plausible answer, especially with modern gender equality, the rules in place at the time of Charles' birth still dictate the line of succession. Similarly, while a grandson could potentially be in line for the throne, he would only be if his father, the Queen's son, was no longer alive. So, in this case, the oldest son is the correct answer because he is next in line according to the established rules of succession.