Previous research revealed that monolingual children between 11- and 13-year old show a target-like production with respect to gender assignment of definite determiners whereas this is not the case for bilingual children who massively overgeneralize de. In order to further investigate this overgeneralization, the paper designed an experimental decision task, “tapping the knowledge” of both monolingual and bilingual children. Results show that bilinguals fail to represent abstract gender and that de and het are in free variation. The difference between the production and comprehension data could suggest that bilinguals have some awareness of de and het being gender markers. In that case, the overgeneralization in the production data is possibly not a grammatical phenomenon, but more likely a speech production strategy.