Andrew Sullivan's blog The Dish had a remarkable post this morning, concerning an article by Fred Clark that appeared in the www.patheos.com blog slacktivist. The article has the title, "The 'biblical view' that's younger than the Happy Meal," and it documents that until about 30 years ago, mainstream popular evangelical leaders such as Norman Geisler actually argued for the permissibility of abortion under some circumstances; they didn't believe that life begins at conception. Clark also documents that this fact has been completely airbrushed out of evangelical media, which he underscores by repeating a refrain from Orwell: 'we have always been at war with Eastasia!'
Now, of course, evangelicals now profess belief that life begins at conception, when the egg is fertilized by the sperm. This might be perfectly sincere, and it might be valuable politically to the conservatives who now advance that position. But it's unfortunate, because in fact the prior evangelical position was the sensible and morally correct position, and it was compassionate.
It is the morally correct position for the following reasons. Conception is not a logical beginning point for human life, because occasionally, fertilized eggs fission, producing two individuals, identical (monozygotic) twins. So the theory that one fertilized egg equals one individual is not true. Instead, a much more logical beginning point for human life is "brain birth," when the central nervous system forms and becomes active. This happens at about the point where the embryo becomes a fetus, at about 8 weeks. This would mirror the common criterion for end of life, "brain death," the permanent cessation of central nervous system activity.
Setting a criterion for the permissibility of abortion at 8 weeks might be too soon for some pro-abortion people. But it still allows termination of the pregnancy when profound defects are detected before a human life has begun. This is why the "brain birth" criterion for the beginning of life is much more compassionate that a "pro-life" position that results in the suffering of children born with severe defects. The brain birth criterion also renders morally innocuous the use of embryonic stem cells for medical research and eventual therapies---research that bears great promise for the treatment of conditions such as blindness or paralysis.