Jenny, the embryo is building the body to provide life support when outside the female's body. During this time the human being (the human organism you want to open for cannibalism because he or she hasn't yet built the entire nervous system) is being sustained by the first organ he or she made for survival, an organ that will be discarded when born. Do you know for certain when there is a soul present with the body of the being alive in the womb? If you cannot tell at what age this soul becomes resident with the organism growing and thriving in the womb, then why slaughter them for cannibalistic intent?
Eugenics Alert!
"Man scans with scrupulous care the character and pedigree of his
horses, cattle, and dogs before he matches them; but when he comes
to his own marriage he rarely, or never, takes any such care. He is
impelled by nearly the same motives as the lower animals, when they
are left to their own free choice, though he is in so far superior
to them that he highly values mental charms and virtues. On the
other hand he is strongly attracted by mere wealth or rank. Yet he
might by selection do something not only for the bodily constitution
and frame of his offspring, but for their intellectual and moral
qualities. Both sexes ought to refrain from marriage if they are in
any marked degree inferior in body or mind; but such hopes are Utopian
and will never be even partially realised until the laws of
inheritance are thoroughly known. Everyone does good service, who aids
towards this end. When the principles of breeding and inheritance
are better understood, we shall not hear ignorant members of our
legislature rejecting with scorn a plan for ascertaining whether or
not consanguineous marriages are injurious to man.
The advancement of the welfare of mankind is a most intricate
problem: all ought to refrain from marriage who cannot avoid abject
poverty for their children; for poverty is not only a great evil,
but tends to its own increase by leading to recklessness in
marriage. On the other hand, as Mr. Galton has remarked, if the
prudent avoid marriage, whilst the reckless marry, the inferior
members tend to supplant the better members of society. Man, like
every other animal, has no doubt advanced to his present high
condition through a struggle for existence consequent on his rapid
multiplication; and if he is to advance still higher, it is to be
feared that he must remain subject to a severe struggle. Otherwise
he would sink into indolence, and the more gifted men would not be
more successful in the battle of life than the less gifted. Hence
our natural rate of increase, though leading to many and obvious
evils, must not be greatly diminished by any means. There should be
open competition for all men; and the most able should not be
prevented by laws or customs from succeeding best and rearing the
largest number of offspring. Important as the struggle for existence
has been and even still is, yet as far as the highest part of man's
nature is concerned there are other agencies more important. For the
moral qualities are advanced, either directly or indirectly, much more
through the effects of habit, the reasoning powers, instruction,
religion, &c., than through natural selection; though to this latter
agency may be safely attributed the social instincts, which afforded
the basis for the development of the moral sense."
Darwin
http://www.infidels.org/library/historical/charles_darwin/descent_of_man/chapter_21.html
It's generally agreed upon in this society that the "soul" "leaves the body" when a person's brain stops functioning for the last time. Brain-death is the generally accepted "definitive" criteria for determining whether a person has died or not.
The concept of a person dying simply does not apply before there is a brain to stop functioning.
(Unless you have a different criteria that you use to determine when a person has died than the rest of us...?)
p.s. There is a legitimate debate over whether brain death should mean cessation of higher brain functions, or all functions down to the brain stem, or something in between. I actually gravitate toward a more stringent definition such as brain-stem activity. But an embryo that doesn't even have neurons yet, let alone a brain stem, simply cannot be said to be "a person who has died". Not unless you are willing to redefine "death" to absurd extremes.
Since an early-stage embryo has no brain, they simply are not a person yet. That's a fundamental difference from a 16-18 week embryo that the author gives as an example.
Also, a correction to my earlier post: The neural system starts to exist in some form more like week 5, not week 8.