Your life span may partly be a gift from your dad, a new study suggests.

This isn’t a present that comes with a bow on top. It can’t be bought or written into a will.

It also doesn’t guarantee a long life. But it might be a head start.

The inheritance in question is the length of your telomeres. Those are the tips of chromosomes, which house DNA.

Telomere length may be inherited from fathers, Swedish scientists report in the online early edition of Proceedings of the National Academy of Sciences.

So what, you ask? That’s where the life span question comes into play.

Lessons From the Earth's Elders

Longer Telomere, Longer Life?

Science doesn’t understand everything about aging and life span. No one has it all figured out.

But telomeres have been attracting attention from researchers. Telomere length has been linked to life span. Longer telomeres have been associated with longer lives and vice versa.

A cell’s telomeres shorten a bit each time that cell divides. Over time, that adds up and may be part of the natural aging process.

Swedish Study

Telomere length may be passed down from fathers to their sons and daughters, report Katarina Nordfjall and colleagues from Sweden’s Umea University.

They studied telomere length in 132 healthy people from 49 unrelated families in northern Sweden.

Older people and men tend to have shorter telomeres. The researchers took that into account.

But they didn’t follow those families for years and years, waiting to see who lived the longest or who aged well. The study amounted to a snapshot of telomere length, plus some complex calculations.

What About Mom?

Children’s telomere length tended to follow father’s telomere length. Though kids get half of their DNA from their moms, telomere length didn’t correlate between mothers and either sons or daughters, the researchers report.

That contradicts another recent study of more than 300 people. That report, published in The Lancet in 2004, tied telomere length to moms, not dads.

How could the two findings be so different? They were based on different groups of people and used different methods to estimate telomere length, note Nordfjall and colleagues.

Science may still be a little bit stumped by the family tree when it comes to telomere length. Expect more work in this area in the future.

Meanwhile, don’t expect your telomeres to do all the work. Do what you can to take care of yourself, day by day. Wear your seatbelt, don’t smoke, stay active, and eat healthfully -- all the things wise parents would recommend, regardless of their telomere length.

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By Miranda Hitti, reviewed by Louise Chang, MD

SOURCES: Nordfjall, K. Proceedings of the National Academy of Sciences, online early edition, Oct. 24-28, 2005. WebMD Medical News: “Is Life Span Inherited From Your Parents?” News release, Proceedings of the National Academy of Sciences.