I think very often when we think we are aiming at the best for our children, what we are really doing is trying to position them for competitive success in an intensely driven kind of society. I'm not sure that always leads to the good life or to happiness.

It is true that the Jewish tradition emphasizes the moral mandate to save life. It also has a different position from the Catholic Church on the moral status of the embryo. It has a more developmental view of when human life, in the sense of personhood, begins than does the Catholic Church.

If we go too far down the road of choosing the genetic traits of children, my worry is that parenting will be less a kind of school for humility than it should be, and we will become too accustomed to regarding children as instruments of our ambition and of our desires.

In natural pregnancy, more than half of fertilized eggs fail to implant or are otherwise lost. Should we regard that as an instance of infant mortality? And if so, why are we not mounting ambitious public health campaigns to try to save and rescue all of the fertilized eggs that are lost in natural pregnancy? We would need a public health campaign of massive proportions if there really were over a fifty percent rate of infant mortality.

Parental love is not contingent on the talents and attributes the child happens to have. We choose our friends and spouses at least partly on the basis of qualities we find attractive. But we do not choose our children. Their qualities are unpredictable, and even the most conscientious parents cannot be held wholly responsible for the kind of child they have. That is why parenthood, more than other human relationships, teaches what the theologian William F. May calls an “openness to the unbidden.

I do not argue that nature is sacrosanct in the sense that we must never tamper with nature. That would disempower, really, all of medicine. That would mean that we can't combat dread diseases - malaria, polio, all of which are given by nature, if one thinks about it.

I am trying to get at the moral arguments and the ethical status of various attempts at enhancement, or genetic engineering, or the bid for designer children. But there are implications for society at large.