Back in the day, George Pal had a script for a sequel to his classic movie, "The Time Machine". Rod Taylor, Yvette Mimieux and Alan Young were to reprise their roles as George, Weena and James (not David) Filby.
The story was George is racing backward in Time so his very pregnant wife, Weena, would give birth to his son in Victorian England, only a blast during WWII destroys the Time Machine during it's jouney backward. George and Weena are killed by schapnel. But Weena had given birth to the child just before she dies. James Filby, recognizing George as the man inquiring about his father -from the previous movie, rescues the child and raises him as his own. The child grows to manhood, discovers his true father's plans of the Time Machine, builds his own modern version, a sets off into the future to meet his father before he had been born, and on to his own adventures.
The movie never had been made, of course. But the screenplay had been made into a book aptly titled, "Time Machine II".