Robert De Niro had originally planned on merely providing a brief cameo for the film. However, after Director Nick Hamm heard De Niro would be interested in his project, he asked De Niro to participate in a few more scenes that were all filmed within a week. De Niro later regretted this because his name was "splashed over all the advertisements".
Before the release of this movie, Lions Gate Films set up two official websites: one conventional site with movie information, and one site that appeared to be a promotional tool for the (fictional) cloning institute depicted in the movie. The website gave an email address and phone number (1-888-699-2672) for the "Godsend Institute;" calling the number resulted in a recorded message giving the institute's office hours. Several news outlets reported that when a few bereaved parents called or emailed the fake institute to inquire about having their children genetically reconstituted, the studio started responding to them and explaining that it was just a movie tie-in and not a real laboratory. Similar advertisements for fictional medical procedures and clinics were also produced as parts of the advertising campaigns for Gattaca (1997) and Eternal Sunshine of the Spotless Mind (2004).
Five different endings were shot for this movie, and the released one is the tamest one.
The snow scene in the graveyard was unplanned. It was hoped the snow would remain until the scene was completed, and it was.
The operating room sequences were filmed inside the empty swimming pool of the institute complex.