Based on Lopes and Cyrino (2005) and Creus e Menuzzi (2005), thepurpose of this work is to investigate how Brazilian Portuguese (BP)children are filling the anaphoric direct object position once occupiedby 3rd person accusative clitics. Since these clitics disappeared fromBP’s pronominal system, we aim to determine the linguistic evidencesavailable to children in order for them to choose between a lexicalpronoun or a null object in this position. Results from our analysis ofthe language acquisition data confirmed Lopes & Cyrino’s hypothesisthat the semantic features of animacy and specificity in the antecedentare responsible for the alternation between lexical pronoun and nullobject, as well as bring into question some of Creus & Menuzzi’spredictions, which ascribe to the semantic genre of the antecedent (andnot to animacy and specificity) the main role in the choice of positions.