I found myself thinking of the fabled Octomom this morning, and reflecting that while families were often very large in pre-industrial eras of history, primarily due to lack of birth control and high infant mortality that meant you needed to have lots of kids to be sure of being supported in your old age, no-one prior to the age of modern medicine would have dreamed of having eight children in a single pregnancy and having mother or children survive.
Prior to IVF, it was simply ... inconceivable. ;)