Having kids is a part of the vast majority of peoples' plans for their lives, whether a specific visualized intent or an assumed inevitability. However for those who can't have biological children, or who have not been able to participate in the raising of those children, or whose children are grown and not much involved with your life, there is a vast need for nurturing kids in many various ways, directly and personally, or by supporting the community's providing for kids. The need is almost infinite, and even fairly privileged kids gain a lot from having adults who take a responsible interest in them. It's not a substitute for bringing up your own brood, but it is a huge offering. Remember your best teachers, coaches, neighbors who took an interest, aunts, uncles, and adults you admired from a distance? A lot of parenting was done me by people besides my parents, who worked pretty hard at it too.