Some people never have children. God made this promise to the Israelites and not the church:

(Exodus 23:25-26 NIV) Worship the LORD your God, and his blessing will be on your food and water. I will take away sickness from among you, {26} and none will miscarry or be barren in your land. I will give you a full life span.

(Exodus 15:26 NIV) He said, "If you listen carefully to the voice of the LORD your God and do what is right in his eyes, if you pay attention to his commands and keep all his decrees, I will not bring on you any of the diseases I brought on the Egyptians, for I am the LORD, who heals you."

My first wife was a wonderful, godly woman. She was the sweetest woman I ever met. She died of kidney disease when she was 30 years old. Before that our two children were stillborn.