Is it all right to continue to plead to God for children?

Genesis 25:21Isaac pleaded with the Lord on behalf of his wife, because she was unable to have children. The Lord answered Isaac’s prayer, and Rebekah became pregnant with twins.

Genesis 30:22God remembered Rachel’s plight and answered her prayers by enabling her to have children.

Psalm 5:3Listen to my voice in the morning, Lord. Each morning I bring my requests to you and wait expectantly.

Luke 18:1One day Jesus told his disciples a story to show that they should always pray and never give up.

Because we believe in God, we should pray. Because we believe in miracles, we should pray. Then we need to let God be God. Even when short on hope, we should pray. He is good, he loves us, and he knows what is best for us.