In order to find a relation between Danish male and female, synthetic vowels, a set of female vowels was developed within the framework of a Danish text-to-speech system [1]. A panel of 37 naive listeners judged the vowels to be convincingly female. The female vowels were compared to a set of synthetic male vowels previously developed for the text-to-speech system. Through this work a simple formant transformation between male and female vowels, was found.