I recently read “The Screwfly Solution” by James Tiptree Jr., although I think it was published under a different psuedonym, Raccoona Sheldon, all pen names for the actual person Alice Sheldon. Identity and gender politics aside, it is gratifying to find another strand in the web of sci-fi concepts – the story has to be a big part of the lineage for Y: The Last Man.
I’m not sure if Brian K. Vaughan has read the story or is aware of it (is that a requirement in sci-fi geneaology?), but there are definitely some shared themes, mainly gender extermination through biological agents. I don’t think that detracts from Y – Vaughan has made these themes his own – just as I think The Outer Limits and Watchmen can coexist without one harming the other.