For countless people in the world, having kids of their own is one of the greatest accomplishments they could achieve.
However, like Prince William and Kate Middleton, this royal couple won't have custody of their children.
Due to a 300-year-old rule, the sovereign, in this case Queen Elizabeth II, has the legal custody over her grandchildren.
"The sovereign has legal custody of the minor grandchildren," royal expert Marlene Koenig told News.com.au.
She explained that the law dates back to King George I who ruled over England in the early 1700s.
"He did it because he had a very poor relationship with his son, the future King George II, so they had this law passed that meant the King was the guardian of his grandchildren," she said.
Even though the law passed in 1717 and then again in 1772, new legislation has never been made and the custody law still stands today.
The founder of the Royal Musings blog revealed that this rule has affected the way the royals are able to raise their children, as they must depend on the monarch to approve of their upbringing, education, and travel decisions.
When up to the sixth in line for the throne decides to wed, the sovereign must approve of the marriage as well.
“When [Princes Harry and William] were little, Prince Charles asked the Queen if both children could fly on a plane together to Scotland, to which the Queen said yes,” Koenig said.
“Technically, they needed permission for travel. The Queen has the last word on parenting decisions like that.”
Following Princess Diana's tragic passing in 1997, her will stated she wished for her mother and brother to be William and Harry's legal guardians.
But because of this law, her wish was overruled.
Although it's not specifically stated if the Queen has custody of her great-grandchildren, when Prince Charles becomes King, he'll make the final call on all of the decisions related to the youngsters.
Luckily for his children, Koenig doesn't believe Charles would intervene in their parenting decisions.
“He understands they want to raise their children privately … the only thing Charles might ask for is more pictures,” the royal expert joked.
What do you think about this bizarre law? Let us know in the comments!