Louise Machinist, a Pittsburgh clinical psychologist, had noticed that her ex-mother-in-law, who lived alone, was lonely in a large house in Upstate New York. Since her ex-mother-in-law didn’t need all that space, and because the home was expensive and difficult to maintain on her own, maybe she could live with one or two others, Machinist suggested.

That idea didn’t fly with her former mother-in-law, but it did get Machinist thinking: When she herself got older, rather than living solo and feeling isolated, why not share a house with other single women? She mentioned the idea to church friends Karen Bush and Jean McQuillan. The suggestion of shared housing intrigued them, too—and not just for the future.