The most salient example (but not the most statistically significant) is that everyone I talked to about this who were on the higher end of the intelligence scale had clear memory of their parents responding "I don't know, let's find out" to their curiosity when they were a child, while everyone else I talked to had no such memory.

You know, smart (especially academic) parents are more likely to say that :). This is not a simple issue, I think this is actually a question about how much parent-provided environment mediates the effect of the parent IQ. Mediation analysis is subtle.