06/05/2018 12:06 EDT | Updated 04/12/2019 10:42 EDT

Meghan Markle And Prince Harry's Future Daughters Won’t Have Any Royal Titles

But their future sons will have plenty.

The countdown to the newest Royal baby's arrival is definitely on. And while Prince Harry and his pregnant wife Meghan, the Duchess of Sussex, say they have decided to keep plans around their first baby's arrival private, what isn't private is what the baby's royal title will be.

While the royal couple is now known as the Duke and Duchess of Sussex, it turns out that only their male children will inherit this dukedom thanks to an outdated peerage law, People magazine reports.

The Duke and Duchess of Sussex attend the Prince of Wales' 70th Birthday Garden Party at Buckingham Palace on May 22.

Thanks to this rule, one of the royal couple's male heirs will not only inherit the title of Duke of Sussex, but also their father's Scottish and Northern Irish titles: Earl of Dumbarton and Baron Kilkeel. And if Harry and Markle have no sons, their royal titles will die out.

What title will the couple's daughters have?

According to Hello magazine, they will be known as Ladies and will only be granted the title of duchess if they marry a duke, as Markle has done. However, Royal Central noted that Queen Elizabeth II has the power to grant hereditary peerage if she wants to.

The Queen has amended outdated royal laws in the past with the approval of the U.K. government and Commonwealth countries.

Most notably, Her Majesty altered the rules of succession, which previously stated all male siblings could jump ahead of their sisters, no matter their birth order. In 2011, 16 Commonwealth countries — including Canada, Australia and Jamaica — voted and agreed to change this law, BBC News reports.

The system was then replaced with absolute primogeniture so that succession would be based on birth order and would not discriminate against female siblings.

This means the Duke and Duchess of Cambridge's daughter, Princess Charlotte, is still fourth-in-line to the throne, despite the birth of her baby brother Prince Louis in April.

Why won't Harry and Markle's future kids be called prince or princess?

The Cambridges' eldest son, Prince George, was the only royal great-grandchild to be guaranteed this title based on the 1917 Letters Patent issued by King George V. However, the Queen updated the letters to allow for all of the Cambridge children to be given the title of prince or princess.

This means Harry and Markle's future children will not receive these titles either, unless the Queen declares it, Time reports.

With a file from Charmaine Noronha.