On Aug. 4, 1997, Jeanne Calment passed away in a nursing home in France. The Reaper comes for us all, of course, but he was in no hurry for Mrs. Calment. She died at age 122, setting a record for human longevity.

Jan Vijg doubts we will see the likes of her again. True, people have been living to greater ages over the past few decades. But now, he says, we have reached the upper limit of human longevity.

“It seems highly likely we have reached our ceiling,” said Dr. Vijg, an expert on aging at the Albert Einstein College of Medicine. “From now on, this is it. Humans will never get older than 115.”

Dr. Vijg and his graduate students Xiao Dong and Brandon Milholland published the evidence for this pessimistic prediction on Wednesday in the journal Nature. It’s the latest volley in a long-running debate among scientists about whether there’s a natural barrier to the human life span.