The present study compares the voice quality of female and male speech in two languages: Czech, a Slavic language, and Danish, a Germanic language. For both languages, the results based on a total of 120 vocally healthy speakers are in line with the claim that females are universally breathier than males. This was supported by the Cepstral Peak Prominence (CPP) and H1*-H2* measures, which are generally known as the most robust correlates of breathiness, and also by the H1*-A3* measure. However, the sex distinction was unsupported or even contradictory when using some other measures suggested to reflect breathiness, which provides an incentive to insist on employing a number of acoustic measures in future voice research. The perceptual component of the study nevertheless suggests that these contradictory findings are due to differences in perceived roughness rather than breathiness, and that CPP and H1*-H2* do reflect breathiness differences, and CPP in particular. We therefore conclude that it is indeed the case that female speakers are breathier than male speakers. Finally, in terms of the two robust measures (CPP and H1*-H2*), no language-specific differences in the magnitude of the effect of sex on breathiness were found.