As men get older, their DNA matures—and when that genetic
material is passed on to children, it may mean a longer life for
the kids, researchers find. Thus kids with older dads and
grandfathers may be "genetically programmed" for higher life
expectancies, the BBC reports. It all comes down to telomeres,
the structures that protect the ends of chromosomes. Telomeres
in the majority of cells shrink as they get older—but it's the
opposite with sperm cells. In sperm cells, telomeres get longer
as a person gets older; if these longer telomeres are passed to
children, it can mean longer telomeres, and longer lives, for
the next generation. A relatively old paternal grandfather can
mean even longer telomeres in a child. If fathers keep having
children at older ages, it could mean longer life expectancy for
the greater population, researchers say. But that doesn't
necessarily mean men should delay having kids: Doing so boosts
the risk of miscarriage.