Al Mohler on willful childlessness. He often causes a stir on this subject. I'm more interested on the topic of when to have children, not whether. But it's helpful, nonetheless.
The church must help this society regain itssanity on the gift of children. Willful barrenness and chosen childlessness must be named as moral rebellion. To demand that marriage means sex -- but not children -- is to defraud the creator of His joy and pleasure in seeing the saints raising His children. That is just the way it is. No kidding.