Goat glands are the answer!

A blastocyte is not a fetus. Nor is a fetus necessarily viable. Nor is a viable fetus necessarily...well, do a websearch for images using the term "acephalic" (I've seen these, in the flesh, along with what were then called "frog babies", and I cried along with the parents). WARNING: don't do this unless you have a very strong stomach.