I don't think I have ever once heard a non-religious argument against abortion.
While I'm sure such arguments exist (ex: medical complications), I've yet to hear any from pro-lifers I know, and I've been on both sides of the debate
It's barbaric. It deprives the child of ITS right to life, liberty, and the pursuit of happiness.
-=Mike
And the "right to life" argument almost always falls back upon a set of religious arguments, in my experience.