Here's something I've been thinking about for some time, and would like to hear what people believe-- the human cloning thread made me think of this again.
One serious problem, which humanity has brought upon itself, is that we have removed ourselves from the natural cycle of selection, and thus we become a dysgenic population -- the quality of our gene pool, if you will, is dropping.
One example, one that we can already see quite clearly the effects of, is that we have removed the strong selection pressure for good eyesight. In nature, an animal which has poor eyesight is usually killed quicker than one with better eyesight, so on the whole, there is a relatively strong pressure to eliminate alleles (an allele = a possible form of a gene) which cause poor eyesight.
For millenia, humans have lived in communities, and, although those with lesser eyesight were not always treated as well as those with, the reproductive success of those with poor eyesight was not nearly as reduced as it would be in a natural environment. So, the selection which normally "purifies" the gene pool, by reducing the ability of undesirable alleles to reach future generations, has been removed.
In turn, there are a huge number of humans at the present who have myopia or other vision impairments. Nowadays, with corrective lenses, selection for good eyesight pretty much goes away altogether -- if individuals with the genes which cause myopia, et al, are not less successful at reproduction than those without, the allele(s) which cause myopia will not naturally be removed from the population.
This can also be applied to any other characteristics which we have removed the natural selection upon.
Given that we have significantly altered our species' natural ability to weed out "defective" alleles, do you think we should use our technology to replace this "purifying" behavior? By this, once we develop the ability to selectively genetically alter a living being (which will probably happen in our lifetimes), should we use this ability to correct defective alleles (like those which cause myopia) and reduce the prevalence of these alleles in the population?
If we should do this, should we also use this ability to improve the human race in general? I.e. make ourselves smarter, stronger, faster, etc.?