A. That's a bit like asking, "Is it wrong not to marry?" Obviously not! But when the apostle Paul, for example, chose not to marry, he saw it as a sacrifice for the sake of Christ (1 Corinthians 9:5). Paul was willing to give up something good for the greater good of his special calling from God.
Similar principles apply to this question. Declining God's gift of children is a choice never to be taken lightly. However, while the well-known words of Genesis 1:28 to "be fruitful and multiply" seem at first glance to communicate a biblical mandate to couples to bear children, this verse actually communicates a blessing from God to the human race.
As Genesis 1:28 says, "God blessed them and said, 'Be fruitful and increase in number.'" The Hebrew grammar utilized in this passage is the same used in other parts of Scripture to express prayers and wishes of blessings upon families (see Genesis 24:60). So the statement to "be fruitful" doesn't refer to what couples must do to please God, but what God can do for and through humankind.
Sometimes circumstances guide the decision not to have children: It's time to finish an educational degree, or health issues or a genetic condition make having kids unwise. Occasionally a couple may feel the world is such a bad place they fear bringing more children into it. But this fear forgets that "perfect love drives out fear" (1 John 4:18). Christians need to trust that God's ultimate love triumphs over the terrors of history and that he will keep our children and us in his hands through thick and thin.