Saviour siblings are children that are born in order to help cure their older sibling that is affected with a fatal disease by providing them with a cell or tissue transplant. This process is done through in vitro fertilization and a process called pre-implantation genetic diagnosis (PGD). PGD involves creating embryos outside of the body and selecting the ones that are free of any diseases or abnormalities and that are compatible with the affected child; these embryos are then implanted in the mother's uterus while the unwanted embryos are disposed of. 

 

This sort of genetic screening is also common for couples that have a history of genetic disorder in their family and are susceptible of transfering that gene to their future children. PGD is used as a method of preventing heritable genetic diseases, by screening the embryos before they are implanted, to ensure a healthy baby is born.

PGD is a fairly new procedure that was intoroduced in 2001. While it has many great benefits, this is a highly controversial issue, since it involves the potential exploitation of one child while trying to save another. Also, while using PGD can definitely lead to having an easier life with the certainty of having a healthy child, there is also the ethical issue of discarding the unwanted embryos.