Genes and diseases tested for by PGD
Until 2006, the Human Fertilisation and Embryology Authority (HFEA), only allowed people to use PGD to test embryos for disease genes linked to very serious, life-threatening genetic illnesses. Couples would only do this if they knew that one of them carried genes for a particular disease. PGD is often used to test for genes such as those for cystic fibrosis or sickle cell anaemia. If a baby has a gene for a serious illness like this, then there is almost a 100% chance that the baby will develop the disease early in life.
However, the HFEA has now allowed PGD for other diseases that occur later in life such as genetically-inherited breast and bowel cancer. Even if a person possesses a gene that increases their chance of getting these diseases, they are much less certain of developing them because they occur when the person is much older.
Some people are concerned that the rules for PGD are becoming too lenient. By allowing scientists to test for genes linked to diseases people might not necessarily develop, they worry that scientists may soon start testing for eye colour and other features, which are cosmetic rather than disease linked. This might begin a trend in ‘designer babies’. Most people find this idea very controversial.
Selection of genes for disability
There are also concerns that PGD may remove some genes from the population for good. Some people with genetic characteristics such as deafness, fear that their culture and identity may be eliminated.
Scientists still have a lot to understand about the activity of genes in the body. It may be wrong to eliminate genes if we do not know exactly what they do.