Abortion: The Evolution Connection by Jake Hebert, Ph.D., and Michael Stamp
Within a consistent evolutionary worldview, there is no logical basis for moral absolutes. If mankind is truly a cosmic accident, then there is no Creator-God to whom we must give an account, and there is no logical and objective basis for claiming that a given action is morally right or wrong.
In such an amoral worldview, it's perfectly "natural" for the strong to prey upon the weak, as often occurs among animals in the wild. And if it's natural for the animal, it's also natural for strong humans to discard the weak. An individual might claim that he prefers that a frail human not be harmed, but is one's mere preference an objective basis from which to make a moral claim that applies to all people?
Read more: http://www.icr.org/article/7414/