First, it is scientifically impossible to discover a precise point when the individual alive being transitions from 'only' embryonic to 'fully fetal' in nature. Because that topic is deeply dependent on not so easily explained scientific facts, allow me to move to the next objection to such an arbitrary asignment of value.
It is generally because of the organs being present in the embryo that the arbitrary assignment of fetus is made. Prior to the 'fetal age' of the individual life, the organs necessary for survival as a 'fully functional human being' are not present but are being built by the embryo and looped into the primitive brain, the brain stem. If this is what will be chosen to define an alive individual human being (at the earliest fetal age), it is important to note that the first organ built by the newly conceived individual is cast off at birth! The placenta is the first organ necessary for the survival of the human organism. This organ is so important that even at in vitro fertilization clinics, the technician/physician will not seek to implant an embryo conceived in a petri dish until the organ is already surrounding and protecting the embryonic life. It is the organ of placenta that sends the chemical signals to the woman's uterine lining that initiate implantation and thus further life support from the woman's body. That is why the choice of fetal age is so arbitrary in the false assertion that fetuses should be protected while embryos should not (should not, based on the specious notion of an integrated whole organism functioning for survival and growth and development only when the fetal age, with the organ structures for future survival are in situ, is reached).
In science, it is most often the simplest solution that is the most elegant solution to a problem. Since the embryo builds its own survival capsule (the placenta) to allow it to have shelter and nourishment, it is elegantly factual to assert that the embryo is an alive, integrated whole for that age of its lifetime begun at conception. The embryo is no less an individual human being with at least one functioning organ that allows the integrated whole to survive into the future ages of the lifetime already 'up and running'."