Screening before we know: radical uncertainties in expanded prenatal genetics

In this article, we discuss the radical uncertainties unleashed by expanded prenatal genetics. We show how we are now routinely screening fetuses in the absence of two essential sorts of information. At the population level, we do not have sound, unbiased data about the prevalence, penetrance, and clinical variability of most mutations. At the level of the proband, it is often too soon to discern relevant information about the fetus’ phenotype. First, we outline the longstanding ethical objections to newborn screening for poorly understood genetic anomalies and disorders, and explain how it limits our understanding of their penetrance and variability. Next, we contrast the strong restrictions and regulations around newborn screening with the more laissez-faire framework for prenatal screening, using the rollout of non-invasive prenatal testing (NIPT) as the timeliest and most illuminating example. We show how new conditions are added to NIPT kits based on technological feasibility and profit motive, leading to widespread prenatal screening for incompletely understood genetic disorders. Finally, we explore the myriad dilemmas that ‘screening before we know’ creates for counsellors, caregivers, and prospective parents in the age of non-invasive prenatal genetic screening, and argue for an approach that openly embraces the radical uncertainties we face