Asked about whether her religious affiliation directly influences her writing, Willis said (Source: OMNI Visions transcript, 4 Dec. 1997.):
I think writers have to tell the truth as they know it. On the other hand, I think every truly religious person is a heretic at heart because you can't be true to an established agenda. You have to be true to what you think. I think Madeleine L'Engle and C.S. Lewis both have times when they become apologists for religion rather than writers. I want always to be a writer, and if my religion is what has to go, so be it. The story is everything.In a 1996 Science Fiction Weekly interview, Willis said: "I sing soprano in a Congregationalist church choir. It is my belief that everything you need to know about the world can be learned in a church choir." [Source]