In the summer of 1950, a young Harvard graduate student named Thomas F. O’Dea traveled to Salt Lake City and met with a veritable who’s who of Mormon intellectuals and church leaders. O’Dea was preparing for a trip to a Mormon community in New Mexico as part of Harvard’s “Comparative Study of Values in Five Cultures Project.” O’Dea’s papers contain meticulous notes of these meetings,and I am currently writing an article about the influences of the personalities he met during this trip on his 1957 book The Mormons. One of the most interesting moments recorded by O’Dea involved a visit to the home of Elder John A. Widtsoe. Widstoe told O’Dea and his wife that
if we were very well behaved he would show us the Mormon wonder of wonders, which very few Gentiles got to see. We both expressed immediate interest. He said it was the “De-horning Room,’ suggesting that we realized that Mormons were born with horns and had too have them removed at an early age. 
O’Dea’s tone, and the fact that Widtsoe had to explain himself, suggests that Widtsoe’s joke fell flat, at least in part because O’Dea had never heard the myth about Mormons having horns. I wonder the degree to which this stereotype was widely circulated. It clearly draws on anti-semitic imagery from the Middle Ages in which Jews were portrayed as semi-human creatures with horns and tails. I have heard it told only by Mormons as evidence of the stupidity of anti-Mormons. How about you? Have you heard the one about Mormons having horns? If so, in what context?
 “Meeting with Apostle John A. Widtsoe at His Home, 1425 Sigsbee AVE, SLC, 29 July 1950.” Thomas F. O’Dea Papers, MSS 1417, Box 5, fd 7, L. Tom Perry Special Collections, BYU.