Can an atheist logically oppose abortion?

Many Christians have a rather distorted view of what "atheism" is and what "atheists" think. Or, at least, what the Christians think that "atheism" should be like, if taken to its logical conclusion and extreme (and, thus, if an "atheist" does not hold these positions exactly, he's "not really an atheist"). This is particularly common among American Christians (especially those of the fundamentalist persuasion), but is also somewhat common elsewhere as well (especially since in the last couple decades American Christians have been so effective at spreading their belief system all over the world via the internet).

One of these distorted views is that atheism cannot have any sort of objective morality, no objective moral principles. Which, when talking about this particular subject, would mean that atheism does not put any value on someone else's life, and thus an atheist cannot logically and consistently oppose abortion.

These Christians invariably fail to understand that the modern concept of human rights, which has been described by many philosophers and authors over the past centuries, and inscribed in fundamental documents like the Universal Declaration of Human Rights and the Constitutions and laws of many countries, are largely of secular origin. Concepts like freedom of speech, freedom of the press, freedom of religion, universal suffrage, abolition of slavery, and all kinds of other universal rights (ie. the rights are the same for everybody regardless of anything) are not of religious origin, but of secular origin. They are the product of centuries of secular philosophy, built upon even more centuries of history and politics, learning about what works and what does not work for the betterment of humanity.

If one were to be asked to name the one fundamental human right that supersedes every other, the most important one, which one would it be? If one had to choose one single fundamental human right, and put it above everything else, which one would it be?

I think that most people would agree that it would be the right to life.

This is the one right that, when infringed, can be considered the worst crime against a person, above everything else. This is the one right that must be most fundamentally protected by governments.

It is perfectly possible to give a 100% secular atheistic argument for this fundamental human right, based on sociology, political theory, secular ethical theory, biology and even evolutionary theory. There's absolutely nothing inconsistent about a purely secular atheistic world view, and the view that the right to life is the most fundamental human right.

Thus, it's perfectly possible for an atheist to be against abortion, without any sort of ideological contradiction or inconsistency. There is nothing controversial about this.