One of the ways in which parenting is a learning experience and an opportunity for moral growth is that we learn as parents that we don't choose the kind of child that we have.

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.

It's possible to make sense of what's morally at stake in an appreciation of the gift of life, or the gift of a child, without necessarily presupposing that there is a giver. What matters is that the gift - in this case, the child - not be wholly our own doing, our own product.

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.

It's true that to speak of an ethic of giftedness, which is very much the ethic that I deploy in raising questions about designer children and genetic engineering - an appreciation of the giftedness of the child or the giftedness of life does have religious resonance, because a great many religious traditions emphasize the sense in which the good things in life are not all our own doing; they are gifts from God.

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.

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.