Richard' I subscribe to Ancestry.com and I find no one named Penn Childs in any U.S. Military databases nor U.S. Federal Census records 1790 to 1930. But there is a large family named Childs living in Pennsylvania and "Penn" was how the state was abbrevated back then. Now it is PA. Could be "Penn" was a nick name because he was from Pennsylvania with last name Childs. (I am a Military brat and rembember my dads friends were sometimes called by the state they came from with last name, especially if one than one person with the same surname was in a unit, barrack, command.) Since you descend from a son of your grandfather, you carry the Y gene of your family surname same as your father and grandfather. You might try a DNA test with a company that has a "Childs DNA project" of family group already tested or large database of surnames. You may find a match or cousin or connect with another male that takes a test later.