Savage Grace (2007)

This examination of a famous scandal from the 1970s explores the relationship between Barbara Baekeland and her only son, Antony. Barbara, a lonely social climber unhappily married to the wealthy but remote plastics heir Brooks Baekeland, dotes on Antony, who is homosexual. As Barbara tries to "cure" Antony of his sexuality -- sometimes by seducing him herself -- the groundwork is laid for a murderous tragedy.

Source: TMDb