My guess is that eugenics experiments on humans would most likely turn in to disaster, not just from ethical perspective, but from the desired outcome perspective.
For animals, it's routine to target a specific trait such as more milk or less aggressiveness and do planned breeding to successfully get the desired outcome. However what we forget is that those animals suffer from many side effects when their one feature is amplified out of proportion. For instance, you can successfully get dog that is super small or super large but they would suffer from severe issues such as bad eyesight or frickle bones. For humans, this gets far more complicated. The intelligence is hardly indicated by ill-defined measurements such as IQ. We don't even dare quantify "creativity" and "taste" which are often drivers to major breakthroughs. In any case, let's say if you do try human breeding to target these qualities and you do end up with people with very high IQ - you can count on lots of potential side effects such as schizophrenia and other mental disorders that dominates lives of people with such out-of-proportion amplified characteristics. On the other end there is a strong argument for random trials, aka, let nature decide evolution. Most high-impact human beings, from Newton to Einstein to Hawking were not the product of other high impact human beings or even high IQ parents, for that matter. They spontaneously appeared on the scene and many times nurture played much stronger role in any case.
If selective breeding based exclusively on IQ criteria would produce significant number of individuals with schizophrenia and other mental disorders then I would just update the breeding criteria to eliminate those unwanted traits from the gene pool as well. After all, evolution is all about trials and errors.
You'll probably end up with each guy trying to find the best girl he can, and each girl trying to find the best guy she can... Evolution proved it to work :) We should concentrate instead on removing impediments to this, such as arranged marriages, rapes and accidental pregnancies... Contraception is helpful on the latter...
Natural selection works fine, but relying exclusively on it might be dangerous for the human species in the longer run. Millions of species have died out because they were unable to adapt to the changing environment fast enough.
In the near future (in evolutionary timeline) in order to survive we might be forced to colonise other planets or cooperate with machines that are orders of magnitude more intelligent than we are today. We either learn how to adapt rapidly or we will be out of the evolutionary game.
For animals, it's routine to target a specific trait such as more milk or less aggressiveness and do planned breeding to successfully get the desired outcome. However what we forget is that those animals suffer from many side effects when their one feature is amplified out of proportion. For instance, you can successfully get dog that is super small or super large but they would suffer from severe issues such as bad eyesight or frickle bones. For humans, this gets far more complicated. The intelligence is hardly indicated by ill-defined measurements such as IQ. We don't even dare quantify "creativity" and "taste" which are often drivers to major breakthroughs. In any case, let's say if you do try human breeding to target these qualities and you do end up with people with very high IQ - you can count on lots of potential side effects such as schizophrenia and other mental disorders that dominates lives of people with such out-of-proportion amplified characteristics. On the other end there is a strong argument for random trials, aka, let nature decide evolution. Most high-impact human beings, from Newton to Einstein to Hawking were not the product of other high impact human beings or even high IQ parents, for that matter. They spontaneously appeared on the scene and many times nurture played much stronger role in any case.