My tiny son struggled for every breath as we raced to the emergency room. His first asthma attack terrified both of us. Over the next decade, he suffered frequent, frightening bouts of asthma. Then, miraculously, he outgrew his suffocating illness. He is now a healthy adult who plays sports and hikes and climbs in his beloved Colorado mountains.

I feel so lucky. Some of my friends aren't as fortunate. One has a daughter slowly wasting away from a hereditary disease. Another lost a two-year-old son from an inherited illness, while a third watched helplessly as three nieces and nephews died in their early teens from a shared genetic disorder.

Parents will do almost anything to spare their children anguish. Yet, even in their suffering, children bring joy with their humor and courage. All this comes to mind as I ponder the decision of the Chicago mother who genetically tested her eggs before in vitro implantation. She wanted to make sure her children did not inherit her gene for the terrible early-onset Alzheimer's disease.

I cannot fault her for her decision. Given the chance, I would probably do the same thing. But, I also wonder what other human qualities may be "selected out" when one ensures that a particular gene is not in an embryo. Is there something remarkable that will never happen? Or only suffering that will be avoided?

Natural selection has undergone extraordinary change since Darwin first wrote about evolution. Medical advances allow us to fight disease with genetic therapies as well as to avoid passing genetic defects to our offspring. While there is always talk of limiting these technologies, using them only for specified treatments, there is no going backwards.

We worry about using carefully selected embryos to produce the "perfect" child, brilliant, attractive, a little super-human. Most of us believe that selecting an embryo for gender or certain desirable physical characteristics is unethical. But, where and how do we draw the line? When people want something that is available, but restricted, they will find ways to get it. There will always be doctors or quacks or clinics somewhere in the world to profit from someone's desire to obtain a prohibited service or drug or technology.

We should also worry that the ability to select a healthy or desirable human embryo will be available only to the rich. Unable to afford such care, poor people will continue to have children who could be subject to genetic diseases they carry. What, then, is the impact on a health system where the rich need fewer services and the poor need more? Will we be living Hitler's dream of a powerful super race dominating all lesser beings?

The Chicago mom has given us the opportunity to debate ethical questions on both personal and societal levels. There are no easy answers. I am trying to figure out my own personal ethical guidelines for using genetic selection technology. Several seem appropriate to me.

I would genetically select an embryo if I knew I carried a gene for a terminal illness that would destroy my child. I would not do so to obtain what I thought were desirable physical or mental characteristics or to eliminate the chance of diseases that are treatable but debilitating. I would probably not make such a choice if the odds of passing on a faulty gene were low.

We cannot legislate ethics; these are intensely personal decisions. We cannot know the unforeseen consequences of making such genetic choices because we will never know the contributions of the children who never were. I cannot imagine a world without the joy my three children have brought to it. But, I also cannot imagine how I would deal with the certain agony they would suffer if I passed on a terrible genetic disease to them.

Medical technology has given us wondrous tools to improve the quality of human lives. It has also given us grave ethical dilemmas. We must look to our own most deeply held values to make the right choices. No one else can do it for us.