And this is from someone who is pro-choice:

Think about what’s being dismissed here as “politics” and “ideology.” You don’t have to equate embryos with full-grown human beings—I don’t—to appreciate the danger of exploiting them. Embryos are the beginnings of people. They’re not parts of people. They’re the whole thing, in very early form. Harvesting them, whether for research or medicine, is different from harvesting other kinds of cells. It’s the difference between using an object and using a subject. How long can we grow this subject before dismembering it to get useful cells? How far should we strip-mine humanity in order to save it?