QUR’AN 76:19 -- And round about them will (serve) boys of everlasting youth. If you see them, you would think them scattered pearls.
Again, the youthfulness of the servants in heaven is repeated with: 52:24: "And they will be waited on by their youthful servants like spotless pearls."
Oh, how enticing for Muslims!
In all seriousness, traditionally the Janissaries were an instrumental force in Muslim military conquests, including parts of Europe. Not all Janissaries were created in this way, but with many of them what would happen is the Muslims would take over a village, sodomize the boys repeatedly for years, then when the boys were teens tell them over and over that the best way to regain their honor is to kill in the name of Islam.