To have grandchildren is not only to be given something but to be given something back.
You are given back something of your children's childhood all those years ago. You are given back something of what it was like to be a young parent. You are given back something of your own childhood even, as on creaking knees you get down on the floor to play tiddlywinks, or sing about Old MacDonald and his farm, or watch Saturday morning cartoons till you're cross-eyed.
It is not only your own genes that are part of your grandchildren but the genes of all sorts of people they never knew but who, through them, will play some part in times and places they never dreamed of. And of course along with your genes, they will also carry their memories of you into those times and places too the afternoon you lay in the hammock with them watching the breezes blow, the face you made when one of them stuck out a tongue dyed Popsicle blue at you, the time you got a splinter out for one of them with the tweezers of your Swiss army knife. On some distant day they will hold grandchildren of their own with the same hands you once held them by as you searched the beach at low tide for Spanish gold.
In the meantime, they are the freshest and fairest you have. After you're gone, it is mainly because of them that the earth will not be as if you never walked on it.
~originally published in Beyond Words