In this article, we investigated children's acquisition of short- and long-distance whose-questions to see whether children know that, in English, the entire whose-phrase must pied-pipe to the specifier of complementizer phrase. Languages vary parametrically on this point, with some languages (e.g., Chamorro, Tzotzil, Hungarian) allowing both pied-piped possessive determiner phrases (DPs) and subextraction of wh-Possessors, and others (e.g., the Germanic languages) requiring pied-piping of the entire whose-DP. In the Minimalist theory (Chomsky (1995)), the computational system is constrained by economy principles that require only a [+wh] feature (or corresponding wh-word) be checked in its scope position; pied-piping of the residue is enforced at the Phonetic Form (PF) interface. In an elicited production experiment with 12 English-speaking children, we found that some children produced split whose-questions such as “Who do you think 's flower fell off?” or “Who do you think 's sunglasses Pocahontas tried on?” We argue that such questions are not the product of a (late) misset parameter but stem from the principles of “natural economy” that constrain the language acquisition device. In child grammar, principles of economy override the PF conditions requiring pied-piping of the entire whose-DP.