How old was your father when you were born? Say an extra "thanks, Dad" this Father's Day if he was a little older than average. New research from Northwestern University shows that the longer fathers, and even grandfathers and other male ancestors, waited to have children, the more likely that their offspring will live longer and healthier lives.
How much longer? There's no set number. Basically, every year gives a slight, incremental advantage to offspring, according to a study published in the Proceedings of the National Academy of Science.
The new research points to the magic of telomeres -- the DNA at the end of chromosomes, reports FoxNews.com. Every time a cell divides, telomeres grow shorter. Longer telomeres are often associated with slower aging, while shorter telomeres are associated with aging-related health declines. People with longer telomeres are known to be more likely to live to 100, for example.
In a 30-year study of more than 1,700 young adults in the Philippines, children of older fathers were found to inherit longer telomeres. And this inheritance held true across multiple generations. So 25-year-old fathers gave their kids longer telomeres than did 20-year-old dads, with incremental gains each year thereafter.
Why? The telomeres in older men's sperm are longer, compared to the telomeres in their blood, perhaps because an enzyme called telomerase, which helps extend the length of telomeres, which is very active in the testes. Researchers say it could also be that stem cells with shorter telomere lengths may die out as a man ages, leaving the longer ones.
At first glance, the study is a contrast to previous research indicating that reproducing younger is better because older dads have more children with birth defects and other health disorders. Not so, says lead researcher Dan Eisenberg. "I don't think this contradicts those other findings, and we don't recommend people have kids at a later age," he says. His study compared differences between men within the usual childbearing years -- not those at the advanced end of reproduction. The more replications of sperm cells that occur as a man ages, the greater the tendency for mutations to occur, which explains the health disadvantages of fathering kids at 50 and up. So both bodies of research can be true.
The evolutionary reasons for the advantages of older dads giving their kids longer telomeres -- and a shot at a longer life -- remain to be discovered, he says.
It's a pretty nice gift, though.
Image by Flickr user mricon, used under a Creative Commons license.