In The Stepford Wives (1975), the husbands secretly replace their wives with robots.
The film follows Joanna Eberhart after she moves with her family to the apparently perfect community of Stepford, Connecticut. Joanna notices that the town's women seem increasingly devoted to housework, obedience, and domestic perfection. Her suspicions lead her to discover that the men's association is involved in replacing the original women with lifelike mechanical duplicates.
The robot wives are designed to reproduce the appearance of the husbands' spouses while removing independence and dissatisfaction. The story uses science fiction horror to criticize sexist expectations and the pressure to turn women into idealized household servants.
The novel by Ira Levin was published in 1972, three years before the film. The 2004 remake has a different tone and plot treatment, but the 1975 film is the version most closely associated with the original unsettling reveal.