Likewise, we do not know enough about the genes involved with intelligence to assume that we can give someone both the ability for rote memorization or creativity of thought... or any other facet of performance related to the mind. There are many genes involved with intelligence and changing one can have unknown cascading effects throughout the genome. Even if it were possible to make a child generally "good" in each category of physical and mental performance, is it not likely that this person would end up simply being mediocre? Could a generally "good" genetic profile really compete against someone created to be "perfect" for a specific task?
I'd like to go with your train of thought here and pull things back from the realm of wild speculation to the realm of reasonable speculation. As you're stating, trying to make a solid determination on the specificity of physical traits to genes and their various interactions is, to a large extent, not currently possible. There are exceptions, especially when it comes to straight forward traits like eye color, but obviously the connection between cognition and genetics is unclear (to put it mildly).
As a result of this condition, in the short term (next decade or so) private enterprise which does venture into the field of "new eugenics" is going to favor the more conservative approach of genetic screenings over risky experimentation with genetic engineering. Now the blase transhumanist may be unimpressed by such developments. Yet when viewed in light of the rapidly improving price performance of genotyping technologies, such developments could create profound, even revolutionary, changes in our societal dynamics. Privacy is going to be a major concern, but I believe this concern will be counter balanced by financial incentives resulting from market demand created by genomics databases and their need for "content". The resulting content will be used to create sophisticated screening algorithms which would then provide valuations on the viability of embryos. Again, privacy (both for donors and recipients) and the potential for discrimination become major issues at this point.
Edited by N0NZER0, 19 February 2009 - 06:34 PM.