That's also the hope of Nancy Campbell, a leader of the Quiverfull movement and author of Be Fruitful and Multiply.

"The womb is such a powerful weapon; it's a weapon against the enemy," Campbell says.

Campbell has 35 grandchildren. She and her husband stopped at six kids, and it is her great regret.

"I think, help! Imagine if we had had more of these children!" Campbell says, adding, "My greatest impact is through my children. The more children I have, the more ability I have to impact the world for God."

"We look across the Islamic world and we see that they are outnumbering us in their family size, and they are in many places and many countries taking over those nations, without a jihad, just by multiplication," Campbell says.