My argument is not that we must never intervene in nature. My argument is that there is a moral difference between intervention for the sake of health, to cure or prevent disease, and intervention for the sake of achieving a competitive edge for our kids in a consumer society.

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.

Some parents expend great efforts to get their kids into the right nursery school or the right preschool, with the thought that that will set them on the path to success, to competitive success especially.

The other effect that I worry about is the effect on the parent, that the moral teaching of humility and of the limits to our control that parenthood teaches- - that that will be lost and that we will begin to think of children more as consumer goods than as gifts that we can't fully control and for which we aren't fully responsible.

Markets are useful instruments for organizing productive activity. But unless we want to let the market rewrite the norms that govern social institutions, we need a public debate about the moral limits of markets.

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.

The most fateful change that unfolded during the past three decades was not an increase in greed. It was the expansion of markets, and of market values, into spheres of life where they don’t belong.