The experiment reported in this paper is aimed at determining the influence of non uniform vocal tract growth on the ability to reach acoustic-perceptual targets in English. An articulatory-to-acoustic model integrating non uniform vocal tract growth has been exploited to synthesize 342 5-formant vowels, covering maximal vowel spaces produced by speakers at 5 growth stages: newborn, 4 years old, 10 years old, 16 years old, and 21 years old (adult stage). 37 American English speakers served as subjects in a perceptual categorization experiment. Results show that the three cardinal vowels /i u a/ can be produced by speakers with a newborn-like vocal tract. It is suggested that articulatory-to-acoustic relationships for a given vowel may differ across growth stages.