Thanks. I agree that tool making is an impressive skill, which requires a lot of cognitive resources, some of which might indeed be linked to activation in Broca's area. But here, too, there is no one-to-one correspondence: Broca's area is involved in many behaviors, so the fact that both sentence construction and tool making activate it, does not mean that they rely on the same neural processes, let alone the same genes. The evidence for the link between FOXP2 and tool making would be stronger if there is a family of people with a FOXP2 mutation (like the KE family I mentioned) who are impaired in tool making (or, if such a family does not exist, there could be correlative evidence from population-level studies). Don't know whether such evidence exist, that's why I was asked about the type of evidence you rely on.