Long­term average spectrum (LTAS) analysis has been found to offer representative information on voice timbre. It provides spectral information averaged over a period of time and is particularly useful when persistent spectral features are under investigation. The aim of this study was to compare perceived and actual sex of the recorded voices of children to the LTAS characteristics. A total of 320 children, 20 boys and 20 girls in each of eight age groups (range 3 to 12 years), were recorded singing a nursery rhyme. In an earlier analysis, the recorded voices were evaluated with respect to perceived sex by expert listeners. Mean LTAS analysis for boys and girls groups revealed a peak at 5 kHz for children consistently perceived as boys (whether male or female in actuality), and a flat spectrum at 5 kHz for children consistently perceived as girls.