Black and female professors are less likely than their white, male counterparts to be described as "brilliant" by their students.
According to an analysis of reviews on RateMyProfessor, students are more than twice as likely to call their white, male professors a "genius" than women and African-Americans.
And the stereotype might actually be discouraging those two groups from entering some academic subjects in which they are already poorly represented, such as philosophy and physics.
Daniel Storage, a University of Illinois graduate student who led the study with a psychology professor, said the flattering label was attributed to men more than twice as frequently as women.
"Male professors were described more often as 'brilliant' and 'genius' than female professors in every single field we studied - about two to three times more often," he said.
The study also found that the underrepresentation of women and African-Americans could not be explained by factors such as their average maths scores, a desire to avoid long hours at work, the selectivity of each field, or the ability to think systematically.
"We consistently found that the only thing that was explaining the proportions of women and African-Americans in a particular field was that field's emphasis on the importance of brilliance and genius," he said.
Another 2015 study showed that students who thought "genuis" was a precursor to success most often belonged to subjects where African-Americans and women were underrepresented.
"Both of these groups are stereotyped in a similar way about their intellectual abilities and therefore are potentially affected in a similar way by the amount of emphasis that's put on brilliance," said the author of the study, Professor Cimpian.
