The episode was recorded on May 31, 1989.
This marks the only time in the series that someone besides Maurice LaMarche provides the voice of Egon. Two regular cast members, Frank Welker and Kath Soucie, provide voices for Egon at different stages of his reverse aging. Welder voices the child and toddler Egon while Soucie voices baby Egon (she also provides the voice of the baby at the end of the episode).
Egon regresses through five ages.
Janine didn't appear in this episode as she took the day off in the story. However, Kath Soucie still provides four incidental voices for the episode.