Many members of my family are involved in medicine. I never chose that educational or career path, but I did end up with the basics of math and science to comprehend today's ethical debates. I know very few people in medicine who share the cynical worldview of Dr. House, who is still a totally humane guy compared to eugenicists (those who philosophically favor the "culling" of weaker members of the human race - their definition of weaker, of course) like Peter Singer and current White House "Science Czar" John Holdren. Some people have even written books and coined the term "liberal eugenics" to advocate for the direct ending of human life to improve things for everybody else.
A responsible concern for the balance of health, well-being and the carrying capacity of our world is not the same as full-on eugenics. I agree with most, if not all, of the carefully thought-out positions of Garrett Hardin, the ecologist who authored famous and controversial essays including "Lifeboat Ethics" and "The Tragedy of the Commons." There is a world of difference between someone pointing up that, left unchecked, people can and will despoil group environments (the tragedy of the commons) as Hardin did, and advocating for directly ending people's lives - from infants to adults - as people like Singer and Holdren do. In "Lifeboat Ethics," Garrett Hardin pointed up that providing temporary aid (food, medical aid, and unsustainable economic aid) to people with long-term problems that only they can solve themselves is akin to indefinitely keeping everybody on a lifeboat that has only a tiny amount of food and water. This approach assumes that human life on earth is ultimately a "zero sum game;" however, many would argue that it is NOT a zero-sum game. So far, it has turned out that food capacity has been able to increase, and that as time goes on and technology improves, many natural resources are able to be treated in a renewable manner.
Ultimately, I think, the difference between the three scientists was one of careful thought and consideration. Garrett Hardin's suggestions are just that - suggestions and food for thought. He doesn't say "throw everyone off the lifeboat immediately!" How can the problems best be solved, for the greatest good of all? This type of thinking can lead to solutions. The full-on eugenics thinking of Singer and Holdren leads only to dismay and even potentially violent actions. People like Singer and Holdren ultimately believe in a static world. There is little qualitative difference in the type of thought that advocates blindly providing resources to those in need (unlimited food aid to destitute countries or areas while investing no time or resources in solving the underlying reason food is lacking) and the eugenics and sterilization approaches of Singer and Holdren. Both are simplistic and ignore the fact that life will survive and that people can solve their own problems. What is needed is the means to build a sustainable structure for life, not the deliberate culling of the weak through either active (eugenics, abortion, mass sterilization) or passive (withdrawal of medical care, food, and untreated disease).
In a story called "Perfect Stranger," I wrote about the implications of Liberal Eugenics - i.e. the access of wealthier individuals to genetic engineering for their children, something that will certainly be a reality, if not in my lifetime, then in my daughter's lifetime. In the story, the father Gary came to feel that his son Denny was no longer his own son. Gary was miserable, after allowing his wife to make many choices of genetic "improvements" on their son, ultimately creating a "perfect" teen who was at the same time, totally estranged from his father and mother.
To me, this all boils down to, "What is 'better than'?" With access to gene therapies that could create many "improvements" in a yet-to-be-born child, or even a growing child, do we really as frail humans know what is "best"? Will the gene therapies also affect reproductivity - in other words, will the "improved" children pass their improved traits on to their own children? You might get a resounding "no" from the knowitalls out there; I think otherwise. There is a strong likelihood that genetic manipulation won't affect only the "desired" areas (i.e. eye color, weight, gender, hair color - to name a few that are in current use or development) while leaving reproductive capacity untouched. There is certain to be a difference in impact between the genders as well, given differences in reproductive capacity and means.
I can say that something like changing eye color is probably not a good trade-off, when non-invasive methods can instantly achieve the desired result (colored contact lenses).
The physics of life is as implacable a rule as non-living, static physics of motion, energy and thermal dynamics. Quantum physics merely makes it more of an uncontrollable system. If we change a person on the genetic level (not chromosomes - that was a different series of stories by me) we are without a doubt going to get unintended changes along with the intended ones. Many, if not all, people have instincts about this type of thing. This is why people fear and oppose genetic engineering. It isn't the simplistic fear of a "super race" that is of such concern, it's the real, non-simplistic fear of unintended consequences.
And I have this to say to the Singers and Holdren's of the world. Looking at any individual who you deem "worthy," Singer and Holdren - let's just say looking at yourself - do you have a perfect, unblemished ancestry of only physically and mentally flawless and "outstanding" forebears? In the complex web of human ancestry, can you assure yourself that the lineage from which you arose, was comprised exclusively of people who'd pass your genetic perfection and deserving of life razor? Singer, in your past, were there hunters, or people who dealt in livestock for slaughter? Holdren, was every single one of your ancestors perfect in their use of natural resources and even money?
In all the things that make us who we are - the tangible and intangible - can we make these choices for our own children and grandchildren? Today's profligate march toward command and control mirrors the much less-sophisticated ideas of the 50's, and the horrific experiments in death of the mid-20th Century. What lines did Hitler cut off among the millions who died in World War II? Which person who might have found the cure for cancer or discovered a truly sustainable energy technology had their forebears destroyed in Cambodia, in Rwanda, in Bosnia? In terms of mental illness alone, "genius" often goes hand-in-hand with bipolar disease. My father and his twin brother were alike in almost every way, except that my father was non-mentally-ill and a genius, while his identical twin brother had Schizophrenia. For certain, schizophrenia is one of the conditions frequently targeted for genetic non-reproduction by the Singers and Holdrens of the world. This would be very disturbing to my many cousins, and yes, the world would be a far-poorer place were they and their children and grandchildren not in it.