Classic old movie where a woman is on trial for murder. She finds out the handsom defense attorney is her son. I thought it was with barbara stanwyck?

Madame X (1966)
starring Lana Turner
Madame X (1966) - IMDb (http://www.imdb.com/title/tt0060645/)

You can see a list of other versions here:
Madame X (1966) - Connections - IMDb (http://www.imdb.com/title/tt0060645/trivia?tab=mc&ref_=tt_trv_cnn)

The Lana Turner is the most famous of them.