In reading this chapter you will:
learn about pre-implantation genetic diagnosis;
consider whether it is morally acceptable to select against embryos with diseases and disabilities;
reflect on whether good intentions make an action morally acceptable;
ask about the value of a life compromised by disease or disability;
reflect on whether diseases and/or disabilities are socially constructed;
consider the moral acceptability of ‘saviour siblings’ and gender selection.
In 2003 the Human Genome Project was completed. It sequenced and mapped the human genome, demonstrating there are fewer genes than expected (25–26,000 instead of 80,000–140,000), and that 50% of the genome consists of ‘non-coding DNA’, repeated sequences of DNA that do not code for proteins. The next step – already well advanced – is to identify the functions of the genes that make up the genome, their interactions with each other and with the environment.
We shall be discussing the activities made possible by our understanding of human genetics in several parts of this book. In this chapter we shall consider only using genetic information to test embryos before implantation, and selecting for and against embryos on the basis of such tests.