We offer genetic tests to couples to allow them to select the child - from the possible children they could have - with the best opportunity of having the best life. But how should we decide what constitutes "the best life prospects?"
Each couple makes its own decision about whether or not to have a child with Down's syndrome. "But my value judgement should not be imposed on couples who must bear and rear the child. Nor should the value judgement of doctors, politicians, or the state be imposed directly or indirectly (through the denial of services) on them," he says.
There are good reasons to engage people in dialogue about their decisions, to try to persuade them with arguments, but in the end we should respect their decisions about their own lives.
Reproduction should be about having children who have the best prospects, but we must give individual couples the freedom to act on their own value judgement of what constitutes a life of prospect. That includes the freedom to do what others disapprove of or judge wrong, provided the exercise of freedom does not harm others, he writes.
As rational people, we should all form our own ideas about what is the best life. But to know what is the good life and impose this on others is at best overconfidence - at worst, arrogance, he concludes.