The Roman satirist Juvenal has an interesting passage speaking of rich Roman women:
[H]ardly any woman lies in labour on a gilded bed. So powerful are the skills and drugs of the woman who manufactures sterility and takes the contracts to kill humans inside the belly.
Satire 6, lines 595-97, trans. Susanna Morton Braund, Loeb Classical Library, vol. 91 (2004).
Juvenal flourished in the 120's and 130's A.D., that is, well before Christianity would be a dominating force in Roman society and culture.
What I find interesting about the quote is how Juvenal in a matter of fact way tells us that abortion is "to kill humans inside the belly" (Juvenal's Latin: "homines in ventre necandos").
A more literal translation of this phrase would read: "that human beings be killed in the womb."
Whatever you may think of the modern legal issue of whether a woman has the right to choose to abort, I think we should be able to agree with the intuition of Juvenal: abortion is the killing of a human being in the womb.
So even if you are pro-choice, you should be able to recognize where those of us who are pro-life are. The intuition of the pagan, non-Christian, non-Jewish Juvenal was not based on the Bible or religious belief. His intuition was based on what he thought self-evident to any literate, pagan Roman observer of his time.
Note: See the link at the beginning of this post for other interesting bits of Juvenal.
(Image of Juvenal in public domain)