Why do amphibians return to the water to lay their eggs?

Amphibians originally were water-living creatures, who later on evolved and adapted, therefore coming out of the water to become both land and water animals. However, they cannot change the way they are born, and where they are born. It's always been the same-amphibians will always go into the water to lay their eggs, where the eggs will hatch, and slowly evolve to become accustomed to both environments. It's in the genes or something like that.