It's a hairy issue, but a team of budding young scientists has claimed to have proved blondes really are more dumb.
The fourth year boffins from Drumcree College in Portadown swapped Bunsen burners for feather dusters and questionnaires to probe a series of stress-related stereotypes.
After an in-depth analysis involving hundreds of fellow pupils, the group discovered three quarters of redheads were fiery, 59% of brunettes were boring, and 64% of blondes "below average" in IQ tests.
Their findings will go on display in Dublin this week as part of the BT Young Scientist and Technology Exhibition which features more than 500 projects from schoolchildren north and south of the Border.
More than 80 judges from the worlds of business and academia will interview and assess each project with the overall winner announced at Friday's awards ceremony.
Drumcree College pupil Eimear Creaney said her three-strong team had applied some unconventional research methods.
"For the redheads we did an anger survey and we made them stand with one arm raised and tickled them with a feather to see how they would react," she said.
"We gave the brunettes a fun questionnaire and asked them things like how often do you laugh and what's your favourite colour."
The 14-year-old said some staff members had also taken part in the survey. "There were no dumb teachers but there were boring ones and fiery ones," she added.
Organisers of the exhibition, now in its 46th year, received more than 1,500 projects from a record 329 schools before deciding on the 520 finalists.