Carbon Copy (1981)

Roger Porter (Washington) is the long-lost black son of Walter Whitney (Segal), a respectable businessman who lives in the all-white community of San Marino, California. Walter, who is Jewish, has been hiding that fact for purposes of professional advancement in the business which his anti-Semitic father-in-law (Warden) heads.

Once Roger turns up at Walter's office, it turns out that he is the result of Walter's relationship with a black woman, who is now dead. Walter's father-in-law had warned him that the relationship would be harmful to his career, so he broke it off.

Walter attempts to help Roger by telling his wife Vivian (Saint James) that he wants to adopt him. She accepts, but soon regrets the decision and ends up kicking Walter out. Her father also fires him, taking his car and benefits in the process. Penniless, he and Roger check into a motel, and later move into an apartment. Walter ends up as a menial manual laborer, shovelling horse manure.

The final ten minutes makes the transition from comedy to drama, where Walter has to choose between either acceptance that Roger is his son, or alienation of Roger to salvage his own position in society.