The Age of Desire.

Janet Loring is a young widow with a young son. She marries millionaire Malcolm Trask, but doesn't tell him about her previous marriage or her son, Ranny. Abandoned to the streets by Janet, Ranny eventually moves in with a bookseller and her granddaughter Margy. As the years go by Janet comes to regret abandoning her son and takes out ads looking for him. Marcio, a vicious blackmailer, sends Ranny to Janet posing as her son, not knowing that the young boy actually is her son. Complications ensue.