See another excellent post by Tony Esolen over at MereComments at http://merecomments.typepad.com/merecomments/2009/09/choice-the-dragon.html:
[W]e should conceive of abortion existentially: we should ask what the act is, or does, to the woman who procures it. It is not simply the killing of innocent human life. It is a mother's taking of a life which, unless she has been raped, she herself has conceived, by voluntarily doing what we all know is designed biologically to produce new children. It is therefore deeply unnatural, and is related, alas, to other acts which are now promoted, which are also unnatural; indeed the very category of the "natural" for human behavior is quickly being erased from our common consciousness, and with it any natural end for which human beings strive.
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We should, I think, beware of using the language of the enemy; and the enemy has been bandying that word "choice" about, while political partisans clear across the field assume, without thinking too deeply about it, that choice is an unalloyed good.