They are close enough after "a bit of anti-rejection drugs, or a bit of GMO effort". We can suppress the immune response, one way or another. If the animal is

They are close enough after "a bit of anti-rejection drugs, or a bit of GMO effort". We can suppress the immune response, one way or another. If the animal is unable to clear the placenta after the birth, we lose the animal, but we still get a baby.