Princess Diana’s sister, Lady Sarah McCorquodale, has beautiful red hair, while her other brother and sister — Charles and Jane — both had red-tinted hair when they were younger. The royal line is peppered (er, spiced?) with redheads throughout the family tree, including Queen Victoria, Edward VIII, and today, besides Prince Harry, his cousin Princess Beatrice.
In Markle’s case, none of her immediate family has red hair — her father, Thomas Markle, who is white, seems to be mostly brunette, while her mother, Doria Ragland, who is black, has dark-brown hair similar in color to Meghan's. According to Jamie Spear, a genetic counselor with RMA of Connecticut, race is a factor. “The trait is very uncommon in Africans and African-Americans,” he says. “However, she could still be a carrier from her parent who is Caucasian, depending on the country of origin.”
But the biggest factor in obtaining red hair comes down to one specific gene.
“Red hair is an autosomal recessive trait which, primarily, is due to a gene called MC1R,” explains Scott M. Weissman, a genetics counselor at Chicago Genetic Consultants. “Everyone has two copies of this gene. For a couple to have a child with red hair, each parent has to carry a particular variant in one copy of the MC1R gene that can cause red hair.”
Spear adds that "there are several changes in the MC1R gene that cause red hair. A child would have to inherit two changed copies, one from each parent." That means, "a parent could have two changed genes and be redhead (like Harry), or a person could be a carrier of one change in the gene. Carriers would not have red hair, but could have a child with red hair if a partner had red hair or was also a carrier.”
The lingering question mark is whether someone has passed this red-hair gene down to Meghan. “Since Harry has red hair, if it is due to MC1R, all of his kids would be carriers, and having a child with red hair would depend on whether Meghan is a carrier — but there’s no way to know this,” says Weissman. “If she is a carrier, it would be a 50-50 chance. If she is not a carrier, the chance would be significantly lower.”
Still unclear? As Caleb Heid, a genetics counselor with University of Missouri Health Care, explains, a gene is “basically a sentence that tells your body what to do. In the same way that a sentence can have multiple spelling errors, a gene can have multiple mutations that are inherited in different ways. Sometimes red hair is inherited in an autosomal dominant manner, similar to brown eyes. Other times it is inherited in an autosomal recessive manner, similar to blue eyes.”
But that’s not the end of that.
“It gets even more complicated because some autosomal recessive mutations don’t play nice together,” continues Heid. “You can have two parents with red hair and none of their red-hair mutations in the MC1R gene are compatible; this would cause their children to have brown or blond hair instead.”
In other words?
“The short and simple answer is that it is impossible to exactly guess the likelihood of having a child with red hair,” explains Heid.
One thing we do know is that if Meghan and Prince Harry have a redhead, and then continue to have more children, there’s a 25 to 50 percent chance that their other children will have red hair, says Heid. That’s the only guarantee in terms of redheaded-ness in their case. “Anything else is just guessing.”
Whatever the hair color, we do know one thing — that baby is going to be adorable. Just look at the familial evidence.
This article originally appeared on InStyle U.S.