Tongue Rolling and Your Genes
If you took biology in high school or middle school, your class most likely included a unit on genetics and Gregor Mendel, the "father of modern genetics." Using pea plants, Mendel found that inherited genes play a role in determining the traits living things develop. If you are color blind, for example, it's because you inherited the gene for color blindness from at least one of your parents.
In an attempt to spice things up, teachers often use unusual traits as a way to demonstrate how genes work. One of those traits is whether a person can roll their tongue or not. But here's where things get tricky. Your genes might not actually have much to do with whether or not you can roll your tongue, PBS NewsHour points out. The belief that the ability to roll the tongue comes from a gene dates back to 1940 and research conducted by a scientist named Alfred Sturtevant.
It would be putting it mildly to say that Sturtevant's research was flawed. BBC notes a few of the kids in his study refused to open their mouths. Instead of not including them in the study, he put those kids in the "not able to roll their tongues" category. Additionally, Sturtevant found that some of the kids in the study could roll their tongues, even though their parents couldn't, a fact that pretty much instantly disproves his dominant gene hypothesis.
Eventually, Sturtevant reversed course and realized that his hypothesis that tongue rolling is caused by a dominant gene wasn't quite right. He even later apologized for the mistake. But he might have been a bit too late, as decades later, students across the U.S. are still being taught that tongue rolling is a genetic trait.