The Brood (1979) on Netflix

A man's wife is under the care of an eccentric and unconventional psychologist who uses innovative and theatrical techniques to breach the psychological blocks in his patients. When their daughter comes back from a visit with her mother and is covered with bruises and welts, the father attempts to bar his wife from seeing the daughter but faces resistance from the secretive psychologist. Meanwhile, the wife's mother and father are attacked by strangely deformed children, and the man begins to suspect a connection with the psychologist's methods.