There are a number of genetic diseases which we now know are caused by a defect at a single gene locus. These diseases include haemophilia A, cystic fibrosis, Duchenne muscular dystrophy, sickle cell disease, Huntington’s disease and SCID (severe combined immunodeficiency). Gene therapy offers the hope of introducing healthy genes into the cells of people affected by the diseases, enabling them to function normally and restoring the patient to health. A great deal of work has gone into gene therapy for cystic fibrosis, but success has been very limited. One disease where gene therapy showed great initial promise was in the treatment of SCID – but major problems have arisen there as well (see SCID – a case study).

There are many ethical questions about using such new and experimental techniques on patients who are already very sick. Here are two pairs of commonly expressed opinions, one in favour of treatments such as gene therapy and one against. Use the resources listed below – and any others you chose to use - to find out  about more gene therapy and the progress made so far.  Then from each pair of statements chose the one closest to your own viewpoint. Write one or two paragraphs expressing your opinion, putting forward the main arguments for and against the idea and justifying your position.