Trivia: In the opening scenes, an uncredited Heather Graham plays the mother of the title characters.
Trivia: When Julius visits Vincent in prison, Vincent calls him "Mr. Universe", a title that Arnold Schwarzenegger held for several years, 20 years previously.
Trivia: Marshall Bell, who plays Mr. Webster, appears to be wearing the same trench coat Arnold Schwarzenegger wore in The Terminator.
Trivia: Mary Ann Benedict mentions she had a child once, but he died at birth. This happened in real life to Bonnie Bartlett (who played Mary Ann). In 1961, she gave birth to a child who died 24 hours later.
Trivia: The singer in the nightclub scene is Nicholette Larson who was famous for the song "Lotta Love" (1979).
Chosen answer: Although I wouldn't call one a bad guy, Professor Werner is the the one who raised Julius, and would remain a friend because of this bond. Mary Ann (the twins' mother) however, was told that Julius died at birth and was never told about Vincent. She blames Professor Traven for this (probably since he's the only one around to yell at). Vincent on the other hand was never told his mother died during childbirth and he grew up thinking his mother abandoned him. Until Julius showed up, he never knew he was part of an experiment and he had no knowledge of either doctors and probably no feelings regarding either of them.
Bishop73