Girls are just as good as boys in cathedral choirs, researchers said on Monday.
By Jonathan Amos
BBC News Online science staff, in Salford
They challenged the 500-year-old tradition which claims a group of teenage boys have a quality of voice that their female counterparts cannot match.
Traditionalists say you cannot beat the boys
Professor David Howard, from the University of York, said a controlled experiment in which 130 people listened to boys and girls singing identical pieces of music undermined the theory.
"I believe this argument is primarily sexist. It's got nothing to do with music," he told the British Association's annual science festival, in Salford, Greater Manchester.
"If you have the music the same, the rest of the choir the same, the director of music the same, the acoustic the same, and you just change the top line - you can't tell the difference."
UK cathedral choirs were exclusively male - boys singing treble, men singing alto, tenor, base - until a mother challenged the rule in the European court in 1991, arguing her daughter was a better singer than her son.
Cathedrals were then told to give girls an equal opportunity.
Howard's study involved making recordings of Evensong held on consecutive days at Wells Cathedral in Somerset, but with boys singing one session and girls singing another.
The recordings were randomised and played to listeners who were asked to say whether the top line was being sung by a male or a female group.
The listeners were able to identify the gender of the choristers correctly only 53% of the time.
"It was like sticking a pin in," said Professor Howard.
Despite the European court case and the requirement to open choirs to girls, British cathedrals have yet to make a major step towards mixing the genders.
The practice has been to run parallel male and female groups that rarely sing alongside each other.
"A girl tends to have a voice that people describe as more breathy, more husky - and the boy tends when trained to have a nice, pure voice - something very special. " Professor Howard said. "That's if you listen to one girl against one boy.
"However, when you put them as a group singing the top line, the director of music attempts to get a 'blend' and that 'instrument' is identical to the boys."
He said it was possible directors of music wanted to use these instruments in different ways.
"It could be there is some view held by directors of music that the traditional choir is the boys choir and they want to keep that going, and they've got this new thing and that's the girls choir."