It is consoling for people who have been beautiful to see their beauty born again in their children. For the rest of us there's the melancholy reflection that our buck teeth and knock knees are going down triumphantly to posterity. But how ever hideous children are, to their parents they look beautiful. And that bloom has a purpose. Being young is biologically all about courtship and reproduction.
Youthful beauty is designed to recruit lovers.
Old people have a different sort of beauty. Like fruit in a still life or rocks and minerals in a museum. It's not designed to be sexy. It just shows we are part of nature. Children love the cuddliness of their grandparents - the wispy hair like ducklings down, the speckly skin like thrushes breasts, the ears that have acquired a teddy bear quality.