no kidding about the deep and difficult. If we can get rid of Down's, why stop there? Eventually someone, somewhere, as you pointed out, will try to do more.
Unfortunately, it'll happen with or without regulation.
If only, if only, the woodpecker did cry, all humans were good, and none had to die.
i didn't say everything. You sure about homozygous? I recall reading something about alot of adults in Africa with homozygous who were completely immune to malarity.
The sufferers of the illness have a reduced life span. It is believed that carriers (sickle cell trait) are relatively resistant to malaria. Since the gene is incompletely recessive, carriers have a few sickle red blood cells at all times, not enough to cause symptoms, but enough to give resistance to malaria. Because of this, heterozygotes have a higher fitness than either of the homozygotes.
that five year figure I picked up here, and I should've added "if left uncared for--ie no treatments to alleviate the problem--the child dies soon after birth--soon being a perhaps tortuos five or so years of existence.