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.

Parenthood is a school for humility. We can't choose the precise traits of our children, and that is morally important. It teaches us what William May, a theologian whom I greatly admire, calls "an openness to the unbidden."

I think too often in our society parents, who may have good impulses, overreach and try to mold and shape and direct their child.

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.

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.

I think part of being a parent, to love one's child, is to accept them as they come - not to see them as instruments of our ambition or as creatures to be molded, as if they were themselves commodities.

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.

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.