Population screening to detect carriers of several recessive conditions is now possible. Such screening can be conducted preconceptually, antenatally or neonatally. This raises the question of which programmes should be implemented, and on what basis these decisions should be made. Professional organisations in many countries are responding to these vexed questions by producing reports that set criteria to be met by all genetic screening programmes (Health Council of The Netherlands, 1989; Royal College of Physicians, 1989; Nuffield Council on Bioethics, 1993; Andrews et al., 1994). These reports emphasise the importance of patient autonomy in the decision whether or not to undergo a genetic test. The need to do more good than harm is also stressed. The purpose of this chapter is to consider the extent to which these principles are considered in evaluations of carrier screening programmes. Ways of realising the objectives of genetic screening programmes will then be discussed.

The number and type of screening programmes vary both between and within countries. The most frequently available programmes are for the common recessive conditions (see Table 5.1).

The objectives of carrier testing

To evaluate any clinical service, it is necessary to define its objective(s). Most often the objective is to improve one or more health outcomes. In genetic screening for recessive conditions, there is frequently no health improvement for the affected individual: the most common intervention is the offer of termination for affected pregnancies.