Of all the hair myths floating around out there, one of the most popular has to be the idea that we inherit our hair ― more specifically, whether we’ll lose our hair ― from our mother’s father.
First of all, there are many genes that dictate what our hair looks like, Dr. Christopher Cunniff, clinical geneticist at Weill Cornell Medicine and NewYork-Presbyterian Hospital, explained to HuffPost.
“There’s not one gene for black hair and one gene for blond hair, one gene for wavy hair and one gene for straight hair,” he said. “What’s known is that there are a lot of genes, probably dozens, that influence all of these traits.”
That means it’s not really fair to blame one person for the hair on your head. Sure, your hair traits could come from your mother’s father, but according to Cunniff and Dr. Robert M. Bernstein, a clinical professor of dermatology at Columbia University, there’s a solid chance you inherited your strands from someone else, or more than one person, in your family.
“It is more complex than that,” Cunniff explained to HuffPost, adding, “There’s no good support for the idea that hair distribution or baldness is something that is more inherent in the maternal side than the father’s side.”
Cunniff also said that there is no good support for the idea that hair traits skip generations.
“It really has to do with how those multiple genes combine, because obviously, every one of us is a combination of each of our parents,” Cunniff said.
Bernstein echoed Cunniff, noting that hair traits can come from either side of the family.
“The androgen receptor gene is an X-linked gene, so there’s a slightly greater incidence of it following the mother’s side of the family than the father’s side, but genetic hair loss is polygenetic and the expressivity is very variable, so both sides can contribute to someone’s hair loss,” Bernstein told HuffPost.
He noted, however, that genetic hair loss does come from the mother’s side “a little over half the time.”
According to Cunniff, the ideas and theories surrounding hair loss, and the genetics of hair in general, are thought to be the same for both men and women. However, he explained, there’s a possibility the expression of hair-related genes could differ in males and females.
In more scientific terms, Cunniff reasoned, “Women have two X chromosomes and men have one X and one Y chromosome, so it’s possible there could be differences in women that are not seen in men, or vice versa.”
Genes found on the X chromosome could potentially have sex-specific differences, because women will have copies of the chromosome from their mothers and their fathers, while men will only have copies of the X chromosome from their mothers, Cunniff explained. But, he said, of the genes that have been most clearly identified as having influence on hair texture or color, none have been on the X chromosome.
So if you’ve been blaming a certain person in your family for your receding hairline or gray strands, it’s probably time to let go of that grudge.