John Drummond's parents, Sir Hugh Drummond, Bt and Georgia Dewhurst, were witnesses to the Wold Newton Meteorite strike, and the improved genetic inheritance of that event was passed through him to their remarkable descendents such as Korak, Bulldog Drummond, Richard Hannay and Jongor.
John Drummond married Oread Butler, and their children were William Drummond, Colina Drummond and Nyad Drummond.
The family are described by Philip José Farmer in Tarzan Alive, Doc Savage: His Apocalyptic Life, and "Jongor in the Wold Newton Universe" (the latter article published in Farmerphile #12).