I will answer, and then, since it is easier to attack than to defend, I will respond in kind. First, having children is essential to humankind, if the human race is something which should endure; thus, only under unusual circumstances should people not have children, and cursed with those circumstances, it seems to me that those people are flawed or diminished in light of those in better waters, so to speak.
Also, having children is a boon to those who undertake it--one of the great joys, the grand adventures of the human soul, the blessed gifts of the Almighty--as all things which are difficult but good. Those who partake not in it (let alone those who rend it, may God have mercy on their souls) are left out of a great joy of mankind, for whatever reason, and are thus flawed. Perhaps an arguement could be made that some devote themselves fully to a higher good, and sacrifice that part of their life for Something Higher; and then I would say that those brave souls partake of an adventure which we can have little grasp of--but if we put the ultimate scales aside and weigh in light of the joys of earth alone, I say they are slighted save by blessing and grace from Above. For we of the more human, the lesser reaches of the spirit, I say that children are a blessing not to be lost by one's choosing.
And now I reply: why do you not wish to have children?