What are the ethical issues involved in artificial selection?
What an interesting subject! Humans have been practicing artificial selection for thousands of years. In fact, almost all of our agriculture is the result of the domestication of wild plants through artificial selection. The ethics of artificial selection certainly take on new meaning and new conflict in today's world. We may soon have technology which allows us to make selections at the genetic level rather than indirectly through selective propagation or breeding.
Artificial selection has had many benefits for humans. Increased crop yields, improved nutrition, even the particular traits of our pet dogs are all the result of human intervention. However, there are some downsides to artificial selection. When humans select strongly in favor of particular traits-- like white fur or big seeds-- it causes reduced genetic variability. Genetic variability is really what allows plants and animals to survive under a variety of environmental pressures. Have you ever heard someone say that pure-bred dogs have health problems? This is because their genes have been altered so strongly in favor of certain physical traits that they may also have inherited genetic disease or poor immune function. Something similar can happen to plants. Reduced genetic variability which produces desirable produce but does not offer anything in the way of survivability can cause massive crop failure.
As it relates to humans, artificial selection might sound kind of nice. Wouldn't it be great to eliminate genetic disorders before they ever cause problems in a person's life? Sure! But the capability to make selections at the genetic level promotes the idea that certain traits, certain genotypes, certain phenotypes, and even certain people are more valuable than others. Recall the genocides of the twentieth century which were driven by a desire to create a "pure" race with only desirable traits. These were obviously great violations of personhood and human rights, but think of how technology might allow such dreams to become a reality. Don't forget to consider the important point made above-- reduced genetic variability results in reduced adaptation and survival.