Charles Darwin’s theories about evolution have been a contentious topic for more than 150 years, creating tension between the scientific and religious communities. And unless you are a Darwin scholar, you may not know that these revolutionary ideas also were a topic of discussion between Darwin and his religious wife, Emma. Theirs was a passionate debate about science vs. faith.

The Darwins’ relationship is the basis of Sara Gmitter’s new play, “In the Garden: A Darwinian Love Story,” which is now having its world premiere at Lookingglass Theatre under the direction of Jessica Thebus. The ensemble features Andrew White as Darwin and Rebecca Spence as Emma with Jonathan Babbo, Cindy Gold, Caroline Heffernan and Austin Tichenor taking on multiple roles.

“I think Sara makes this story contemporary,” Thebus says. “She makes Charles and Emma living, breathing people we can relate to immediately.”

Gmitter — who spent 15 years working behind the scenes at Lookingglass as a stage manager, teaching artist and director of the company’s young ensemble — makes her mainstage debut with “In the Garden.” (She is currently adapting Charlotte Bronte’s final novel, “Villette,” for Lookingglass.)

Several years ago Gmitter, who has always been fascinated with the stories of “women hidden in history,” heard an interview with Deborah Heiligman, the author of “Charles and Emma: The Darwin’s Leap of Faith,” and was intrigued to find out more about the couple’s relationship.

“That whole question of God and faith was present throughout their marriage,” Gmitter says. “My mind started turning around ideas about what that would have been like, what conversations they would have had when ‘Origins of the Species’ was published.”

The couple’s letters are available on the Darwin Correspondence Project website (darwinproject.ac.uk) and offered Gmitter a wealth of information.

For instance, in one letter Emma writes: “When I am with you I think all melancholy thoughts keep out of my head but since you are gone some sad ones have forced themselves in, of fear that our opinions on the most important subject should differ widely. My reason tells me that honest & conscientious doubts cannot be a sin, but I feel it would be a painful void between us. I thank you from my heart for your openness with me & I should dread the feeling that you were concealing your opinions from the fear of giving me pain.”

“They wrote amazing letters to each other,” Gmitter, 40, says. “Plus Darwin’s journals and manuscripts also are online. You can follow his thought process on evolution and natural selection. All this information made the research so much more interesting.”

Emma was the first to read “Origins of the Species” and she would help edit the work (in the play, she teases him about his bad spelling and punctuation). She may not have been totally on board, but she was still supportive of his work.

“In the original manuscript, she wrote little notes like, ‘That’s a bold assertion,’ in the margins,” Gmitter says. “Those comments I think really pushed him to think about what he was writing.”

Part of the reason Gmitter is able to bring these characters to life is that she to is experiencing a somewhat similar situation — she is a Quaker and her fiancé is an astrophysicist and an atheist — and has drawn on personal experience.

“There definitely was resonance for me about how we come to terms with our different degrees of spirituality,” she says. “He has opened my mind to the idea that science can be as fascinating and moving to someone as theater can be to me. We may have different ideas about what is beautiful and wonderful, but the feeling at the heart of it is the same.”