But first comes “Gloria: A Life,” starting previews on Oct. 2 at the Daryl Roth Theater and intended to inspire its audience with the admirable, fallible example of the woman at its center. The first act traces Ms. Steinem’s life from her childhood with a mother incapacitated by anxiety and depression, and the second takes the form of a talking circle for the audience.

Introduced years ago by the “Thelma and Louise” screenwriter Callie Khouri, Ms. Steinem and Ms. Lahti, who is 68, have a rapport based on feminism, of course, but also on their Midwestern roots, dysfunctional childhoods and a sense that — as they told me in unison — they were living “the unlived lives” of their mothers. The day after the cast’s first read-through, they got together to talk about it all. These are edited excerpts from the conversation.

Tell me about that feeling about your mothers.

CHRISTINE LAHTI I wrote a story about my mother after she died, and I realized that I had spent so much of my early adult life doing everything I could to not be her. As much as I loved her, I judged her, until I realized that she did the best she could with what was handed to her, which was second-class citizenship.

GLORIA STEINEM The same was true for me, maybe more dramatically, because my mother couldn’t function, and by the time I came along, the period of her life in which she’d been a newspaper reporter and loved her work, I didn’t even know that. So it took me longer to discover who she might have been.

Do you think that this play and the movies are a form of writing about our mothers — about what you and your generation gave birth to, culturally?

LAHTI I had no idea about feminism until 1970. Because of people like Gloria, I had a whole awakening. I thought that being second-class was biological. I remember marching against the war in Vietnam. We were marching with the men, but we were still making the peanut-butter-and-jelly sandwiches.