Some Questions for a Man Who Expects He Could Live to 150

Brian Hanley is 64 years old, and if his experiments go as hoped, his life isn’t yet halfway over.

That’s a pretty large if—the idea of living for a century and a half is not inconceivable, though it is far-fetched at the moment. But what interests me about someone like Hanley, a mathematical biologist who splits his time between California and Idaho, is that, unlike most people, he lives as if it’s a real possibility.

Hanley’s path to super-longevity is still hypothetical. He develops gene therapies through Butterfly Sciences, a small company he founded, and has been testing a therapy on himself that he believes might extend his life span and, crucially, his “healthspan,” the period when he’s in good physical and mental shape. He hopes that future advances—among other difficulties, current gene therapies can’t modify a sufficiently large share of cells in someone’s body—could extend those two spans even