The British government is poised to OK a procedure that screens embryos for genes that greatly increase the risk—but do not necessarily cause—breast cancer. Two couples with strong family histories of the disease are expected to pioneer the technique, already approved in principle, and crank up the debate over "designer babies."
Britain now permits screening for genes that carry a 90% or greater chance of causing disease. Doctors will screen the couples' embryos for the BRCA1 gene, which raises the risk of cancer in adulthood by as much as 80%. Critics fear that the procedure is a gateway to selecting embryos for appearance or intelligence rather than health concerns.