Why are royal sons favoured for the crown?
A really old law that means boys in the Royal Family will always get to the throne before girls could be changed.
At the moment a king or queen's son will always get the top job even if he has older sisters.
But some politicians think this is unfair and want to change the rules so the monarch's oldest child gets the crown - whether a prince or a princess.
The Queen got to Buckingham Palace because her dad was king and she had no brothers.
There's a law called the Act of Settlement which decides who gets the crown next - and this is what they want to change. The Act of Settlement dates back to 1701!
Some politicians argue that the law is out of date and point out that it doesn't happen in other royal families in Europe.
But getting the law changed could take a while. Not only do British politicians have to be happy, but it also needs to be agreed by all the countries in the Commonwealth!
Prince Charles is next in line for the throne, followed by his eldest son Prince William.