Identical twin? Rooker asked. Bruce nodded.

“I think the plan just got changed,” Rooker said.

Because identical twins share the same DNA, Blair’s stem cells would work for Bruce.

“It’d be like getting his own stem cells with no risk of circulating lymphoma (cancer) cells,” Rooker said. The last time the Nebraska Medical Center had an identical twin donate stem cells was four years ago, she said. “It’s pretty rare but it’s an ideal situation.”

But there was a hitch: Bruce and Blair weren’t entirely sure they were identical. For six decades, their mother had insisted that her two boys, born four minutes apart, were fraternal twins. They were delivered in two amniotic sacs, and the medical intern in the room on that day in 1956 said that meant they couldn’t be identical.

“We were pretty sure she was wrong. We always felt we were identical,” Bruce said.