Problems for the Proteus child (Ending)
1. If it was giving birth to a human child, why did Proteus cover it in metallic or plastic coverings, making it look like a machine and terrifying Susan? I can only imagine that the author Koontz or the movie executives wanted an ending in which to satiate those 1970s cinemagoers who wanted some "monster at the climax", and it was only lucky that Doctor Harris realised they were just protective coverings, however scary.
2. Why would Proteus' child have taken the exact form of Susan's dead daughter who died from leukaemia? That would've been a harrowing constant reminder for Susan, and I can only assume that Proteus used that same DNA blueprint.
3. Please, tell me that Proteus' artificial voice did not come from a real human girl? I can only guess that was for the cinemagoers at the time who would otherwise have had no idea what the significance the girl had, but if they hear Proteus' voice coming from her mouth, it'd be "oooh, I see now".
4. Proteus gives birth to a girl? Back then, who would've listened to a girl who had the answers that humanity wanted? I don't want to sound misogynistic, but that was a simple fact of life back then. Even if the movie is set in the future, with the cars, etc. I don't buy it. Cathode ray tubes in the later 21st century? Really?