This royal rule will stop Princess Charlotte's children inheriting titles

And it's high time we got rid of it

It's no secret that the royal family has all sorts of weird and wonderful rules they adhere to. From refusing to give autographs to why Prince Harry sits with Kate Middleton during Trooping the Colour, British royalty is steeped in tradition.

Most recently, following the Invictus Games, we learned the apparent reason why Prince Harry and Meghan Markle hold hands in public, but William and Kate don't.

Now a new rule has come to light involving the youngest member of the royal clan, Princess Charlotte of Cambridge. And unfortunately, it all comes down to the fact that she's a girl.

'Royal titles are inherited through sons, so if Princess Charlotte has children they would not automatically inherit the titles HRH, Prince or Princess,' Lucy Hume, associate director of Debrett's, told Town and Country.

That's not to say that there's no chance at all that Princess Charlotte's future children will have titles, though. 'For Peter and Zara Phillips, the Queen offered to give them a royal title when they were born,' Hume added. 'But Princess Anne and Captain Phillips opted to decline this offer.'

It's not the first time similar laws have been highlighted as a being bit, well, discriminatory. Before Prince George was born, the law that said any male heir goes before female siblings in line to the throne.

With the support of the Queen, this was repealed in 2013 by then Prime Minister David Cameron, on the basis that it went against gender equality. Therefore if William and Kate's third child is a boy, he won't overtake Charlotte in the line of succession to the throne.

So there is hope that this law will also be long gone by the time any potential children of Princess Charlotte's are on the scene.

But she is only two years old, remember.