The proportion of older adults in second or later marriages climbed from 19 percent in 1980 to 30 percent in 2015, according to a study published in the Journals of Gerontology. The number of older adults cohabitating, whose family ties also generally prove less close, has soared as well.

“When divorces occur later in life and children are adults, it really changes the equation,” says Merril Silverstein, professor and chair of sociology and Marjorie Cantor Endowed Professor in Aging.

As parents age, “there’s a lot of negotiation and uncertainties,” Silverstein says. “Who has the right to make decisions for stepparents becomes murky.” Such families can experience what’s called “role ambiguity,” he says, creating doubts about “what the social expectations are.”

Read more in the New York Times article, “When Elder Care Is All in the Stepfamily.”