There have been two cast changes to the kids in the series. The beginning of season two, Emmalin Holden changed from actress Caroline Day to Katelyn Pippy. In season five T.J Leblanc changed from actor Luke Bartleme to Connor Christie. They changed Emmalin Holden's actress because the finale to season one ended on a dark note, and they wanted a more classically trained actress to handle the darker scenes for Emmalin in season 2. TJ's actor was replaced because his father took a fellowship at Harvard and the family moved away from South Carolina, where the show was filmed.
Brian McNamara (Michael Holden) and Kim Delaney (Claudia Joy Holden) both were on the O.C. McNamara played Carson Ward (Luke Ward's father) and Delaney starred as Rebecca Bloom (Sandy Cohen's first love).
In season 6 Roxy and Trevor name their twin sons Drew and Wyatt. Drew is Drew Fuller's first real name and Wyatt and the name of Piper's son in Charmed, a show in which Drew Fuller starred in and Brigid Brannagh guest starred in.