Creation
Clark was created by Geoff Johns and Gary Frank for Doomsday Clock, a squeal comic to Watchmen.
Origin
Clark is the biological son of Mime and Marionette which was kidnapped at birth by Dr. Manhattan.
Doomsday Clock
After his encounter with Superman, Dr. Manhattan became inspired. Dr. Manhattan travel back to his world preventing its destruction. On June 08, 1984 Dr. Manhattan took Clark right after Marionette had given birth to him and decided to raise Clark as his son. Jon named the Clark in honor of Superman. A few years later Jon transferred all his powers into Clark and sent him to live with Dan and Laurie, in hopes that they can raise Clark to be the hero their Earth needs. When Clark arrived at the Dreiberg’s resident he was greeted by their daughter Sally.