If your grandfather was old when he had your father, and your father in turn waited before having you, you may have inherited some life-extending perks. According to a recent study by researchers at Northwestern University, the children and grandchildren of older fathers — in their late 30s to early 50s — have longer telomeres, the tips of chromosomes that may have something to do with good health and longevity.
As people age, telomeres get shorter. So, each time a cell divides, its telomeres shorten — until the cell eventually dies off. But previous studies have shown that children of older fathers have longer telomeres. Lead study author Dan Eisenberg, a doctoral candidate in anthropology at Northwestern, explains that it’s probably because as a man ages, telomeres in his sperm actually get longer.
“Our study shows for the first time that this happens across at least two generations: older fathers not only have offspring with longer telomeres, but their sons also have offspring with longer telomeres,” Eisenberg says.
The research team analyzed data from the Philippines’ Cebu Longitudinal Health and Nutrition Survey, which involved 3,327 women who were pregnant in 1983-84, then followed their children. The researchers examined telomeres in DNA collected from the mothers’ and their children’s blood. They then compared children’s telomere lengths to the ages of their fathers and grandfathers when each successive generation was born.
The older the children’s dads were when they were born, the longer their telomeres, the researchers discovered. The finding held true even when the researchers looked back another generation: the older the kids’ grandfathers were when the children’s fathers were born, the longer the kids’ telomeres. The lengthening effect was compounded from one generation to the next. The researchers found no similar effect from the maternal grandfathers’ side.
The thinking is that generations with longer telomeres may live longer and healthier. The current study didn’t look at health outcomes, but other research has associated telomere length with longevity and diseases like cancer.
The authors theorize that handing down longer telomeres provides an evolutionary advantage. “If your father and grandfather were able to live and reproduce at a later age, this might predict that you yourself live in an environment that is somewhat similar — an environment with less accidental deaths or in which men are only able to find a partner at later ages,” said Eisenberg, in a statement. “In such an environment, investing more in a body capable of reaching these late ages could be an adaptive strategy from an evolutionary perspective.”
However, the authors note that their findings don’t suggest that men should wait to have kids. Older fathers are also more likely to pass on harmful mutations to their children, so it’s not entirely clear whether fathers’ older age is an overall benefit to the health of their offspring. Previous data have linked fathers’ advanced age to higher risks of autism, schizophrenia and bipolar disorder in kids, for example.
Eisenberg says he hopes future research will contribute to the understanding of the evolution of aging, and the ways we adapt to old age.
The study was published in the journal Proceedings of the National Academy of Sciences.