Toggleable deep dark

Because the deep dark will be a more scary biome, and minecraft is played by millions of people including children, I propose there should be an option or gamerule to toggle the generation of the deep dark biome. It could be defaultly set to true and if it was a gamerule, could be toggled with a command like /gamerule Nightmare [true/false]. This would be great  for kids and people who do not handle scary things well. Thank you for reading this proposition and I would be greatful for your support!