What is the value of the human being in the mother's womb?

I rerun this most-read post about when human life begins every time that the discussion resurges, which is usually in the shadow of proposed restrictions on women’s reproductive rights. Strong feelings always seem to trump biological facts. Confusion among politicians appears to be apparent concerning when certain events begin or structures appear; whether to track development from fertilization (conception) or the last menstrual period; and even the distinction between an embryo and a fetus. A 4 or 6 week prenatal human is not a fetus — the difference is not arbitrary, it has biological meaning.