I recognize that "animal" and "life" have become politically loaded words used by some to imply a state of being that might not apply to embryos. However, science should drive agenda, not the other way around. Given the extremely wide range of reproductive and maturational strategies employed by the Animal kingdom, the line you wish to draw is going to be very difficult to support. From where I stand, the possibility that the embryonic stage might be definable as "alive" or "animal" in the purely biological sense does not grant it any more status than I'd grant the common flatworm. The application of a label will not transform an embryo into a person.