The majority of American states had laws by the 1930s that allowed for forced sterilization of socially undesirable categories of people, so-called feeble-minded, for example, and with Hitler culminating in genocide.

Aiming at health, restoring health - that is a goal that is both morally important and limited, because it aims at the restoration of normal human functioning, which is an important part of human flourishing.

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.

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.

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.

If you go back to Adam Smith, you find the idea that markets and market forces operate as an invisible hand. This is the traditional laissez-faire market idea. But today, when economics is increasingly defined as the science of incentive, it becomes clear that the use of incentives involves quite active intervention, either by an economist or a policy maker, in using financial inducements to motivate behavior. In fact, so much though that we now almost take for granted that incentives are central to the subject of economics.

Today if you look at most economic textbooks, economics is not defined by subject matter. It's presented as a science of social choice that applies not only to material goods - not only to flat-screen televisions - but to every decision we make, whether it's to get married, or to stay married, whether to have children and how to educate those children, or how to look after our health.