Mark goes missing in the Sahara Desert, the queen is preoccupied by Thatcher's unabashed revelation that her son is her favorite child. And like many of The Crown's seemingly sensational details, Thatcher's preference for her son over her daughter, Carol, is absolutely true. Here's a primer on the Thatcher children.

The Thatchers' two children, Mark and Carol, are twins.

As depicted in the show, Margaret and businessman Denis Thatcher had a rock-solid marriage that endured for more than 50 years. The couple had two children, twin siblings Mark and Carol, who were born August 15, 1953 in Kensington, London.

Carol has openly discussed how her parents' careers impacted her childhood. "Family rushed past us, eclipsed by the sheer pace of my mother’s career as she worked her way up the greasy political pole,” she said, per a 2013 Guardian report. “And my father’s as well, when he was running his own family business. We never had long, relaxed, talking Sunday lunches.”

The rift between Mark and Carol, which is hinted at in The Crown, is also very real. Margaret Thatcher's clear preference for her son over her daughter—more on that below—can't have helped matters, but the adult twins reportedly have a strained relationship to this day. After Margaret's death in 2013, The Telegraphreported the siblings "cannot bear to be in the same room" and were fighting bitterly over their late mother's estate. Carol decided to auction off a significant number of Margaret's possessions, including handbags, shoes, and mementos, which Mark objected to.

A member of Margaret's political party told The Mail on Sundaythat: "For once, Mark is on the side of the angels. His only concern is to protect his mother's legacy and he thinks this sale is simply abhorrent. They were extraordinarily close and he would never sell anything of hers."

Mark really did go missing in the Sahara Desert.

By the late 1970s, Mark had become widely known as a racing enthusiast. In 1980, he took part in the rarefied 24-hour Le Mans race in northern France—and two years later, he took part in another prestigious event that turned into a week-long crisis.

In 1982, Mark was racing in the Dakar Rally when his car broke down. He and two teammates disappeared for six days in the middle of the Sahara Desert before eventually being found by a military search party. Reading his account of events, it's not a huge mystery how this happened—according to BBC History magazine, Mark wrote in 2004 that he'd "done absolutely no preparation. Nothing. I did half a day’s testing and the day after that we were driving out of the Place de la Concorde in Paris. I was thinking, 'Okay, I wonder how this is going to go?' I soon found out."

Carol was the "less favoured" of the two siblings.

Just as The Crown depicts, Margaret Thatcher had no qualms about making it clear she had a favorite child. According to The Guardian, Mark was much closer with his mother than Carol, who was "very much the twin less favoured by her mother."

In Thatcher's later years, she reportedly began to crave a closer relationship with her daughter, who was by that time not particularly inclined to indulge her. In response to Thatcher's comments about not seeing enough of her children, Carol told The Guardian, "a mother cannot reasonably expect her grownup children to boomerang back, gushing coziness, and make up for lost time. Absentee mum, then gran in overdrive is not an equation that balances."

As for the sibling rivalry, Carol maintains a dry sense of humor about the imbalance. Per the Radio Times, she remarked in 1996: "Mark is married to a beautiful girl, has two fabulous children, and various mansions scattered around the world. I’m an ancient spinster of no fixed abode living in a rented holiday flat in a ski resort. I still don’t measure up awfully well on the Richter scale.”

Carol has written extensively about both her parents.

Carol studied law at University College London but ultimately changed careers and began working as a journalist in Australia in the late 1970s. Per the Radio Times, she started at a newspaper before moving to TV reporting several years later and went on to a successful career as a journalist and media figure.

Despite the long shadow cast by her mother, Carol was able to establish an independent career in the media, per the BBC: "by refusing to be drawn into any political arguments, she avoided fallout from her mother’s many critics." She wrote a book about her father, Below the Parapet, and wrote about her mother at length in her memoir, A Swim-on Part in the Goldfish Bowl. She also produced the 2003 documentary Married to Maggie, an exploration of the Thatcher marriage in which Carol interviewed her father.

In 2005, she also appeared on the ITV reality series I'm A Celebrity... Get Me Out Of Here! and per The Guardian became "a superstar" after a stunt went awry: She "displayed nerves of steel…as she steered a jeep along a makeshift canopy bridge 100 feet above the Australian jungle." When the car plunged off the track, Carol was left "dangling in her harness" but was completely unfazed. She "simply brushed herself down and apologized for damaging the car. Later, she quipped: 'I should have brought my chauffeur.'"

Carol was fired from the BBC in 2009.

Carol's media career came to an undignified end in 2009, when she was working for the BBC as a "roving reporter" on The One Show and made a racist comment about a tennis player. The BBC fired her.