The Holy Norm
"It would also be reassuring to know that defects that limit self-realization and self-satisfaction are the legitimate target [of pre-implantation genetic screening]; that conservation and fuller fruition of humanity as we know it is the goal, not the 'engineering' of new forms of human life."
The Office of Technology Assessment, in trying to justify experiments on animals that aren't permitted with humans, made a related comment:
"The rare human being whose deficiency is complete over a lifespan is nevertheless differently situated from the animal. The condition is a disability - the loss of some skill the person would normally be expected to have. The animal's condition is not disabling, even though it lacks the same skill. The very fact that the human has been deprived of an ability implies that the person has been harmed; a human's failure to acquire an ability means that person is in need of help. The condition of the animal does not call for either inference. This difference, to be sure, makes no mention of rights. Yet it creates a special duty to meet the human need that would not extend to animals. Because the animal without a will has not lost what it was biologically programmed to possess, it 'needs' a will only as a human might 'need' to fly. In neither case does the condition give rise to a moral demand for assistance."
These quotes remind me of a book I read (I thought the title was Deviations, but I haven't found anything by that title on several internet searches so maybe not)[Edit: I found out that it's called The Chrysalids]. Some kind of disaster destroyed civilization as we know it. Although they never outright say so, it's strongly hinted that it was a nuclear war that caused the destruction. Whatever it is, the book is set long afterwards. They have a strong opposition to 'deviations', in plants, animals or people, to the point that the authorities (the government as well as their version of the Bible) have dictated a precise norm for humans and every kind of domestic animal or plant. Deviations from that norm, be they plants, animals or people, are to be killed. The star of the story is a young boy, who, unbeknownst to anyone except a select few, is psychic. He is keeping his power a secret for fear of being destroyed as a deviation.
Although that book had a really dumb ending (which I won't reveal here, in case anyone here reads the book), it's one of the best portrayals I've seen of how atypical children grow to understand their own difference and what it means to their society. And if I can figure out what it's actually called and such, I'll post that here and recommend that people read it. But that's not relevant to my current post.
In that book, the norm (which they capitalized, as the Norm) was considered inherently good and right. Any change from that norm, therefore, was bad. I think a similar idea is present in people who draw a distinction between selecting against traits considered abnormal and selecting against traits considered normal but less desired. They seem to think that normal is something objective, rather than simply a social category, and that something about this 'objective' norm is inherently preferable to any other kind of person. This is believed on such a deep level that it's really hard to even recognize, much less analyze. Most people who believe this have probably never really thought about it.
But that's not what normal really is. Normal is just the features that the vast majority of people share, and is not inherently preferable. I describe this further in this blog entry, with analogies such as genetic immunity to the AIDS virus, which is rare in humans but near-universal in chimpanzees. Just because most people have a certain trait does not mean it is inherently desirable, or that the few who don't are in some way worse off.