In the thirty years since Salisbury became the first Cathedral to introduce girl choristers, debate about the merits of boys' voices compared to girls has continued apace. This paper attempts to give some clarity as to whether boys really do have a naturally 'special' voice, or whether the difference between boys' and girls' choirs (if, indeed, there is one at all) is a result of nurturing, and formal training. The investigation presented here attempted to measure the voice at a point where nurture will have had least impact, using untrained boys and girls in Key Stage 1, and asking them to produce simple steady-state vowels. The experiment found small differences in formants, with girls' voices producing slightly higher frequencies (depending on the vowel). However, with significant variation within each sex, and the difficulty perceiving this difference in a choir setting, the results are not considered grounds for the preferencing of choirboy over choirgirl. Subsequently, the discussion section of this paper assesses other reasons why the tradition may have excluded girls for so long, including consideration of the culture of choirboy and the early gendering of the singing voice.