Erwin Schrödinger came up with a theoretical experiment with everyday objects instead of quantum particles. In this case, a cat in a sealed box with some radioactive material and a geiger counter connected to a hammer, which in turn was placed above a vial of poisonous gas. I know, even if theoretical, it's totally sadistic. That, plus, he obviously did not own a cat. Any given cat would not stay still inside a box just waiting for the hammer to drop on the poison by itself. No, a regular cat would be frantically jumping and scratching and would probably break the vial long before any atomic particle had the opportunity to decay in order to trigger the hammer.
But I digress. During his stay in the box, the cat existed in an unknowable state. If an atom decayed, the Geiger counter would trigger the hammer, breaking the vial and killing the cat. But if no atom decayed during the cat's stay in the box, the cat would be alive. Since it could not be observed, it could not be said whether the cat was alive or dead. It existed instead in the state of both life AND death, just as electrons are both a wave AND a particle until you bother finding out which.
Then there's the interesting postulate of the "many worlds". According to it, when you open the box, the probability does not collapse into one of the two possibilities. Instead the universe branches, and in one world the cat is alive and in the other one the cat is dead. Neat, no?
So, here I am, halfway through the 2ww, in my own little quantum box, waiting for the universe to split and hoping I end up in the right world, where I am, in fact, pregnant.