Preformation: Babies all the way down

How are living things created? Was there some major event of creation where all generations to come were nested inside their ancestors? Or is the creation of life a process starting when paternal and maternal fluids come together?

Before the discovery of cells and atoms, some scientists believed things were infinitely divisible. This led them to the theory that even before a pregnancy there is a small human inside its parent that in turn has all possible children it will have inside itself and so on.

This infinite tower of mini humans was thought to avoid the problem of how things that are not alive can create a living being. In the end this theory of preformationism in embryology found its downfall.