How many times have we been taught that tongue-rolling is genetic? Parents, friends, doctors, and teachers have been trying to convince us for decades. Family studies using twins demonstrated clearly that there are important non-genetic influences on tongue-rolling.
Sturtevant who completed the 1940 study suggesting that there is a large genetic influence on tongue-rolling came to a different conclusion after other studies were made. In 1965 he claimed we should not use tongue rolling to demonstrate basic genetics. In reference to his 1940 study, he said he was, “embarrassed to see it listed in some current works as an established Mendelian case.”