Baroness Ruth Deech: Embryo selection's benefits come with moral dilemmas attached

Despite its name, the technique of preimplantation genetic diagnosis (PGD) involves no genetic manipulations or alterations. It is a way of selecting embryos from among a group that is naturally created by the union of egg and sperm from the would-be mother and father.

PGD is used by couples who are otherwise fertile, but where there is known to be a risk in the family of an inherited genetic condition that is detrimental to health. This selection of embryos, which permits the making of a choice about the characteristics of the next generation, is the one that has been met by responses such as "playing God" and "eugenics". It has provoked arguments about reproductive freedom, the welfare of the baby and the treatment of the disabled.

The most powerful arguments against PGD have come from disabled persons. In the last resort, however, the disabled are merely offended by PGD, not harmed or additionally discriminated against. Their feeling of offence is not as serious as the damage done to those to whom PGD might be denied.

There is no insult intended to the disabled in striving to achieve a child with the normal complement of senses and faculties. On the other hand there is no opprobrium against mothers who continue to carry to term a foetus that has been diagnosed as defective in the womb. This is the case even though one bears in mind the considerable financial cost to society of, say, a Down's Syndrome child once it is in existence. It is worth remembering that a very premature and disabled baby may be kept alive at the insistence of the parents, even though the doctors did not choose to do so and regardless of cost.

In the end, the desire of parents to do the best for their children and to have the healthiest children is too strong to be denied. To take the use of PGD to extremes, one could get a polarisation of society into a genetically privileged elite, and an ordinary unselected under-class born in the usual way. If this seems unacceptable, then the argument for regulation is clear – but this area will always be a worrying one because of the great wrongs done in the 20th century in the name of the greater genetic good.

Baroness Ruth Deech of Cumnor DBE is Gresham Professor of Law. This is an extract from a talk she gave at Gresham College last night