Okay kiddo, so you know how there's a queen or a king who is in charge of England and some other countries, right? Well, when they get too old to be the queen or king anymore... or when they pass away...someone else gets to be the new queen or king.
But did you know that for a really long time, only boys could become the next king? That means, even if the king had a daughter who was really smart and nice and would make a great queen, she wasn't allowed to be the next queen just because she was a girl.
That's not fair, is it? So, in 2013, the government made a new rule called the "Succession to the Crown Act 2013". This law says that both boys AND girls can become the next king or queen, depending on who is first in line.
This means that even if the king has a son and a daughter, the oldest one will get to be the next king or queen, no matter if they're a boy or a girl. And that's a good thing because everyone should have a fair chance to become the next king or queen!