I would also like to challenge the idea that faster = smarter, or earlier = smarter. There are a lot of parents of hares on this board, but there are also tortoise geniuses too. If it were me, I'd work really hard to avoid the idea that a particular subject "belongs" to the kid who is more accelerated in it. The sibling who is moving forward less quickly in math, for example, may end up going quite far into advanced math, maybe even making it an integral part of her career . . . as long as she believes that she is allowed to "own" math, regardless of her sibling.
