The remaining inner cell mass can be injected into a blastocele of the recipient species to acquire its trophoblastic cells.

The cells now forming differentiate into two types, an inner-cell mass growing on the interior of the blastocele and cells growing on the exterior of it.

A blastocoel(e) or blastocele (also called blastocyst cavity, cleavage cavity or segmentation cavity) is the fluid-filled central region of a blastula and mammalian blastocyst.