Sonny Boy (1990)

Small-time crook Slue (Paul L. Smith) sends his lackey, Weasel (Brad Dourif), to steal a car, and they're surprised to find a baby in the backseat. Slue and his transvestite lover, Pearl (David Carradine), decide to keep the child, naming him Sonny Boy. But the sadistic couple torture the boy and cut him off from the outside world, and years later, the teenage Sonny Boy (Michael Griffin) is incapable of functioning in society and is forced to submit to the criminal whims of his "parents."