Communities in which women give birth to the same number of children at a younger age will have a higher growth rate. Ultimately whatever community raises the age of marriage to a higher age than the minimum age for safe conception and childbirth will be outnumbered by communities that set it at the age of safe conception. Raising the age of marriage too high can result in extinction of a community. Whether or not the Quran is factually true this is part of why Islam is defeating Europe