Shetterly - American Civil War Soldiers - Ancestry.com lists male Shetterlys who served, but there was at least one female. TNJN - Old Gray Cemetery's Lantern and Carriage Tour revives past mentions "Margaret Shetterly Pesterfield Haynes, a Civil War nurse, fought to collect her service pension and then helped black nurses do the same."
I like her.
I don't know what was up with the one Shetterly who fought for the Confederacy. Shetterlys tended to be poor farmers, so I doubt he owned slaves, and he may've been fighting for patriotism rather than slavery—there were, after all, slaveowners on both sides of the Civil War. Or he may have been drafted. In any case, I'm descended from the Iowa Shetterlys, so that guy's not part of my bloodline.