I suppose progeny has it's place in the list of goals and objectives of most folks. Perpetuating the species is for the most part an instinctual drive that we seem to have inherited, or were blessed with, whichever you prefer.

Regardless, each of us has a fixed duration, no one lives forever, and whatever may come after our time here is done, I doubt we are going to care much one way or the other what happens to those who will come after, whether they face annihilation from some cosmic source, or they manage to do themselves in as a whole. While it is charitable to consider how our lives and our actions will affect the outcome of our race in the long run, from a practical point of view it doesn't really have that much bearing on our own existence in the here and now. Whatever vested interest we may have in making life a little better for our children's children, it must by necessity wane once our mortal coil is shed. Even for those who believe they may come back, the chance that anything you could do in this lifetime would have a perceivable effect on your next incarnation is far too small to be a motivating factor in your present.

The bottom line is, as Seargent Barnes put it "Everybody gotta die sometime, Red", which to me means that no matter what I do now, I am gonna be gone soon, and even if I come back here again, I am only gonna end up dead again, so I might as well make the most out of the time I have now, try and be respectful of others and the world I live in as if I have to share it with everyone else, and figure that whatever happens after I start my dirt nap, my concerns will be elsewhere then.