There is no chance that gravity will cease to function tomorrow, even if people stop believing in it. In contrast, an imagined order is always in danger of collapse, because it depends upon myths, and myths vanish once people stop believing in them.
A good rule of thumb is ‘Biology enables, Culture forbids.’ Biology is willing to tolerate a very wide spectrum of possibilities. It’s culture that obliges people to realise some possibilities while forbidding others.
Culture tends to argue that it forbids only that which is unnatural. But from a biological perspective, nothing is unnatural. Whatever is possible is by definition also natural.