Some genies come from a bottle, but Genie Dragons (like all dragons), come from eggs. Until they learn to grant the wishes of people, baby Genie Dragons mostly grant their own wishes, which are almost always food-related.
Genie Dragons are one of the most magical dragons in existence. How they fly, without large wings, and how they're able to materialize objects out of thin air, are mysteries.
It's unknown if adult Genie Dragons actually cause the wishes of humans to come true, or if, instead, they create the conditions for humans to fulfill wishes on their own.
Whether Epic Form Genie Dragons grant wishes, or help their owners fulfill wishes themselves, it's undeniable that when you count a Genie Dragon amongst your friends, things start to go your way.