Would it be any more cruel than having children as a serf on a farm, where your family has worked for countless generations, knowing that they're likely to have the same fate?
The whole "cruel to children" aspect is flawed. It only self-identifies individuals with a world view that is very earth-centric. We need a societal system where such a position is seen as an honorable one. That's why I liked the Antarctica bit of the submission. We ALL need to learn and change.