One important area of genetic research has been into stem cells. Professor Martin Evans of Cardiff University took stem cells from mice and grew them in his laboratory.
He genetically altered them, before putting them into the wombs of female mice. The offspring carried the altered gene and passed it on.
This breakthrough, known as gene targeting, has helped to develop new treatments for genetic diseases. Stem cells have the ability to replace damaged cells and treat disease. In 2007, Evans won the Nobel Prize in Medicine for his work.
Currently gene targeting is carried out by treating bone marrow or blood cells, which cannot be passed on to the next generation. However, it could also be done through egg or sperm cells (germline gene therapy), which is more controversial, as the inserted gene would pass down through the generations.
While it could spare future generations in a family from having a particular genetic disorder, it might affect the development of a foetus or have long-term side effects. People who would be affected by germline gene therapy are not yet born, so they can’t choose whether to have the treatment or not.