The Human Fertilisation and Embryology Authority is considering whether to recommend legalisation of “mitochondrial replacement” techniques designed to avoid the transmission of mitochondrial diseases (Report, 17 September 2012). We believe the benefits to a small number of parents are heavily outweighed by the risks to the child and to society. This would be the first instance of regulatory approval for modification of the human germ line. There is a long-standing international consensus that we should not cross this ethical line, since it is likely to lead to a future of genetically modified “designer” babies.
