My Mom Broke Every Rule and Lived to 87. Here’s What the Data Says.

My mother was a savvy merchant and a good woman who danced through her three pregnancies. She indulged in what would be considered today as bad habits. She smoked for years, drank white wine, ate what she wanted, and enjoyed a party more than almost anyone I’ve known.

I used to think it was just Judy being Judy — lucky, stubborn, a full-of-life happy soul.

For decades, lifestyle was supposed to be the key to longevity.

A famous study from the 1990s, which compared the effects of lifestyle and diet on lifespan in Danish twins, concluded that genetics was only 25% of the story. That number held up for 30 years, bolstering the narrative that longevity is a matter of choices.

Buy yourself years. If you didn’t live long, you probably didn’t try hard enough.

That research has been blown up.

This year, a study published in Science, using twin data from Sweden and Denmark, found that genetics contribute to 55% of lifespan — more than double the previous estimate. Other research groups working with the same twin cohorts have reported similar rates, around 50%.

Every study before the 2026 research measured mortality as death.

But there are two types of death: extrinsic mortality, like a car accident or infection, and intrinsic mortality, which is our slow biological unwinding governed by genetics.

Extrinsic deaths appear to muddy the results. Once filtering out extrinsic mortality, researchers could understand how the body ages and fails on its own genetic timelines.

No. For one, that 55% figure does not tell you that any single person is 55% doomed or blessed. It’s a figure collected from a group of people, as if the genes we inherit describe population and not the individual.

And even at 55%, that leaves close to half of our health in our control. Thomas Perls, who runs the New England Centenarian Study at Boston University, said the gap between someone with excellent habits and someone with none can still be worth more than 10 years.

Plenty of opportunity to make good and bad choices.

Lifespan also isn’t governed by one gene that you either won or lost — it’s polygenic, the sum of many small genetic effects. There’s no shortcut gene therapy waiting to save us.

My mother’s biology was generous to her, but she didn't leave me with a genetic guarantee. None of us get that.

I can’t run a twin study on my own mother, so all I can do is to stop pretending it’s all or nothing and take the reins on my choices — the stretching and swimming and sleep and diet. How I want to spend a Tuesday.

Genetics-first vs lifestyle-first longevity enthusiasts have warred 30 years, but they're both right. The real question is not “genes or effort?” but what can you do with the genetic hand you’ve been dealt?

A footnote: The last few years of my Mom's life were hard. That’s where she paid the piper for the smoking, the drinking, the decades of not holding back. Her genes may have bought her 90 years, but I’ve wondered whether better choices would have gotten her to 100, with an easier ending. I miss her.

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