There is no biological basis for the widespread belief that choir boys and girls have different types of singing voice, says a new academic study. Any difference is due to training.

There has been a long-running and sometimes heated debate about the relative worth of boys’ and girls’ voices. Even now some cathedral organists insist that girls’ voices cannot be made to match those of their brothers. The girls are accused of sounding weak or “breathy” while the best boys’ choirs are associated with a strength and clarity of sound.

Yet according to the latest research, teams of musical experts - including choral directors of Anglican cathedrals - were unable to tell the difference between boys’ and girls’ singing, choosing the wrong sex time after time.

The study was conducted by Professor Graham Welch from the Roehampton Institute in London. He assembled a panel of 10 choral experts and asked them to listen to recordings of 15 choirs of different types, each singing the first verse of the carol This is the Truth Sent from Above.

The results were striking. “Listeners were not able to identify the correct gender categories of the choirs at above chance level,” writes Professor Welch in the latest edition of Choir Schools Today magazine. “None of the three individual choir categories, boys, girls, or mixed, was reliably identified.

“Further analysis showed that the sex of the regular choir trainer was significantly related to its perceived sex (irrespective of its true sex). Where a choir’s trainer was male, listeners tended to judge the choir to comprise boys only. Conversely, when the trainer was female, the choir tended to be heard as having girl membership.”

It is only in recent years that girls have been admitted to some of the more prestigious cathedral choirs. They now sing alongside boys in Salisbury (the first to take girls), Exeter, Wells, York and Ripon. York and Ripon started to take girls in the autumn of last year. Other cathedrals, Lincoln and Worcester, for example, run separate girls’ choirs.

“Since the mid-nineteenth century, the mixed voices of boys and girls have been the mainstay of the choirs of all but the larger parish churches, but it is only very recently that the admission of girls to the choirs of our cathedrals has been even considered a possibility,” writes Professor Welch.

The advent of female singers has been accompanied by concern that the Anglican choral tradition may be damaged as choirs look for music to suit mixed voices. This fear, he says, is misplaced.

“We find no evidence in these results that the introduction of girls into cathedral choirs will necessarily have any effect on the choral tone that is produced, nor that the much valued Anglican choral tradition will be changed.

“We may ask why, if tone that is perceived as male-like may be equally well created by a girls-only choir, male trainers should be more likely to encourage “masculine” tone than are women trainers.

“The answers must be sociological ones, in that there are more male trainers of girls-only choirs than there are women trainers of boys-only choirs, and secondly that the choral musical experience of the male trainers who were working with our girls-only and mixed choirs happened to be closely associated with the Anglican choral tradition.”

While the experts were unable to tell if a choir was male or female, there was some consensus about the different types of sound produced. Some choirs, that is, sounded “male” to the audience even if the choir was made up of girls.

“A clear and statisically significant linear trend was found for increased accuracy identifying boy singers with increasing age,” writes Professor Welch. “The younger the male singer the greater the likelihood of his being mistaken as a girl; conversely the older the singer the greater the chance of his being correctly identifed as male.” The younger the girls and boys, the smaller the biological differences between them, and the greater the similarity in sound.