If you don't consider human life "sacred," is there any moral reason not to have an abortion?

The decision to have an abortion is incredibly stigmatized, especially in America. Even those who promote pro-life policies say abortion should be as rare as possible. They may cite the mental and physical anguish of the woman—rather than any moral failure—as the prime reasons unwanted pregnancies are lamentable, but rarely does anyone challenge the underlying implication that the choice to have an abortion is somehow bad, even if in many cases it may be considered the "less bad" option.

I want to understand what has caused this deep-rooted and rarely challenged stigmatization. Does it come only from our religious roots, or is there some other moral argument against abortion?

It may help to compare the impacts of abortion to an everyday event we don't stigmatize—the killing of animals for food, sport, or clothing. Putting aside the religious argument that human life is inherently more valuable than other forms of life, is there any other reason to treat the killing of a human fetus—particularly one at the earlier stages of development—as any worse than the killing of a cow, deer, or chicken? Indeed, the animals we routinely kill have similar, if not greater, capacities to:

  • feel pleasure and pain (their nervous systems are more developed than those of a fetus in early development);
  • experience meaningful emotions (cows in line for slaughterhouses show clear signs of extreme distress); and
  • look forward to future events in their life (there's no proof animals have any conception of their futures, but neither do fetuses).

It seems clear that, from a biological standpoint, the animals we routinely kill have just as much claim to a right to life as a human fetus. Yet we stigmatize one killing and not the other. So something else must be going on here. A whole other discussion could be had about animal rights, but for the time being let's focus on abortion. If we strip away all faith-based arguments, are there any ethical reasons left to oppose abortion?