Meghan Markle and Prince Harry will not be able to pass their titles on to any daughters they may have due to old laws of succession.
In 2013, the Queen passed the Succession to the Crown Act, which stated that succession to the crown would not be determined based on gender.
For Prince William and Kate Middleton’s children, this meant that Princess Charlotte was automatically granted the title of HRH when she was born and retained her place in the line of succession, despite the arrival of younger brother Prince Louis.
But the new gender-neutral rules of succession do not currently apply to all of the peerage system - meaning priority is still given to male heirs regardless of birth order.
For the Duke and Duchess of Sussex, this means that the dukedom can only be inherited by a son, and not a daughter.
If the newlyweds only have daughters, their title will die out altogether.
Royal commentator Richard Fitzwilliams told The Independent: “Under the current system, any child of the Duke and Duchess won’t automatically have a royal title.
“The peerage, unlike the succession to the crown, favours males and if they have only daughters, the title of Sussex could die out as it did before."
Currently, any child born to Prince Harry and Meghan Markle will be a lord or a lady, and not have the title of prince or princess.
However, Fitzwilliams said: “It may well be that the Queen, as she did with William and Kate's children, who are HRHs, will decree that they do.
“This raises an interesting question, what Harry and Meghan, who may prove to be unconventional royal parents when they start a family, want for their children. Edward and Sophie, the Earl and Countess of Wessex, didn't want royal titles which their children were entitled to as children of the son of the monarch.”
Fitzwilliams pointed out the newlyweds may also prefer that their children do not have royal titles - “She and Harry are senior members of the royal family. Will they want HRH or prefer Lord and Lady, which is what they would otherwise be, for their children? We will have to see.”
The laws favouring males likely contradict Meghan’s feminist beliefs - as the newest member of the royal family is and has been an outspoken advocate for women.
On the former actress’s biography page on the royal website, it includes a quote taken from her speech at the UN on International Women’s Day 2015, in which she stated: “I am proud to be a woman and a feminist.”
The current succession laws are under increasing pressure to change by women’s advocacy groups, including the Daughters’ Rights organisation, which has highlighted the unfairness of the rules.