Dear Miss Snark,
I'm just finishing up a novel and will be querying soon. Question: I am the grandchild of a middlingly-famous (deceased) writer. Should I mention this in my query (not up front and center, mind you, but in there somewhere)?
Nothing worse than someone thinking (erroneously of course) that you think writing ability is inherited like bank accounts.
IF you gain representation on your own, the pr department may be able to exploit this connection somehow but as far as an agent goes, the only thing we care about is whether you can write, not Grandmama.