Is it not better to have no children than to be a bad parent, letting children become a nuisance to society and cause suffering?
God is the author of life. It is outside of man’s capacity to give life. When a husband and wife become “one flesh,” they are cooperating with the plan of God for the vocation of marriage. Every child is willed by God. The formation of children is the responsibility of the parents. However, for various reasons, children may not receive the best possible education. Does that mean they are destined for a disastrous end? No. God loves every child and every adult. God continues to invite everyone, despite their wrong choices, to a path of freedom and a blessed life in Him. They have free will and the freedom to respond to God’s call and turn around their lives for the best. We know of people who have become saints despite bad parenting. St. Augustine is one of them. There are many other saints who have had rough childhood.
Also, a decision not to have children might mean cooperation with the mortal sins of abortion and contraception. Or it might involve a decision to abstain from the conjugal union within married life, which is contrary to the very purpose of marriage – which is the union of the spouses and procreation. The greatest temptation for man is to play God, assuming he controls everything.
The questioner here assumes that the destiny of a child is totally in the hands of the parents. It is God who is the sole giver, sustainer and goal of every life on earth. And, despite their difficult childhoods and deviant lifestyles, every child has the free will and freedom to respond to God’s call until the day he dies.