Mark , you most likely have the book "turtles of the united states and Canada" ? this Packard guys research is written about under painted turtle in the reproduction section ...... along with a guy name Paukstis , he's done stuff similar to what you are looking to do ..... I think this Davis guy I quoted maybe assuming on his own that humidity has no influence on sex determination , as it is known to influences size of hatchlings and duration of incubation , both of which have been theorized to have an influence on sex determination ........