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 would include non-medical sex selection as one of those practices that I think is morally questionable and that can carry adverse social consequences.

In some parts of the world, that sex selection for boys - and it's usually for boys - reflects sex discrimination against girls, and it leads to very large imbalances - in China, in Korea, in India - in the population between boys and girls, a vast disproportion of boys to girls, and it reflects really this discriminatory attitude toward girls.

Over the past three decades, markets and market thinking have been reaching into spheres of life traditionally governed by non-market norms. As a result, we've drifted from having a market economy to becoming a market society.

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.

The norm of unconditional parental love, I think, depends on the fact that we don't pick and choose the traits of our children in the way that we pick and choose the features of a car we might order, or a consumer good.

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.