I know this thread has died but just found an interesting bit regarding whether a potential human (embryo) is necessarily equated to a human. Rabbis Abaye and Rav Hisda made this comment in the Talmud:
Rav Ḥisda said: She immerses and partakes of teruma only until forty days after her husband’s death, when there is still no reason for concern, as if she is not pregnant then she is not pregnant. And if she is pregnant, until forty days from conception the fetus is merely water. It is not yet considered a living being, and therefore it does not disqualify its mother from partaking of teruma.