Who were the real-life gynecologists on whose story the film Dead Ringers (1988) was based?

Steven and Cyril Marcus were the real-life gynecologists.

The twins were found dead in their Upper East Side apartment in 1975, having killed themselves with barbiturates.

In the movie, the twins were named Beverly Mantle and Elliot Mantle, both played by Jeremy Irons.

Elliot was the confident, arrogant one; Beverly the shy, sensitive one.