Why are younger brothers higher in the line of succession than their older sisters?
The line of succession to the British throne uses the system of male primogeniture whereby younger sons have precedence over their older sisters. So Prince Andrew and Prince Edward are above their older sister Princess Anne in line of succession, and Prince Edward’s son James is above his sister Louise. If Prince William and Catherine have a first-born daughter and then a son, their son would be next in line to the throne after William. It does however allow the succession to inherit through the female line, so the children of daughters succeed to the throne as is the case with the current Queen. While this may be considered to be out of line with current ‘equal-rights’ thinking and there has been debate about if it should be changed, it has not prevented some of the most successful and longest reigning British monarchs from being queens including Queen Elizabeth I, Queen Victoria and Queen Elizabeth II.
