After watching "Children of Men", I got to thinking about possible ways that mankind might be able to keep reproducing in the circumstances presented in the film. Lets assume that the artificial impregnation actually worked (i.e., the zygote didn't get rejected, and it attached to the wall of the uterus, where it began to grow). Would the result of the pregnancy be a human, an animal, or something in-between? Lets say that the zygote was placed in either a very large or a very small animal (elephant or chihuahua). Would the baby be proportionally sized to the mother? In the case of the elephant, the gestation time would be considerably longer (~2 years?) - how would this affect the baby?