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It is new era where babies can be designed with the help of In vitro fertilization. It has helped for many difficulties with having children. However, it raises a number of ethical issues, one of which is the ability to select for particular traits or diseases using a technique called pre-implantation genetic diagnosis (PGD).

pre-implantation genetic diagnosis was firstly done in 1989 to test embryos fertilized in vitro for inherited diseases such as cystic fibrosis, Huntingdon’s disease, and Fragile-X syndrome or for diseases causes by abnormal chromosome structure, such as Down’s Syndrome. After testing the unaffected embryos are implanted into the mother’s uterus. Earlier, the testing option for couples at risk of passing an inherited condition to their children was by sampling foetal cells from the placenta or amniotic fluid. If a foetus was observed to be affected, parents would then have to choose whether to continue with the pregnancy, or have an abortion.

Pre-implantation genetic diagnosis (PGD)

At the time of in vitro fertilization, eggs are removed from ovaries and fertilized with sperm in a Petri-plate. The fertilized eggs undergo normal cell division (Mitotic) until they have eight cells. At this phase, one or two of these cells are removed. DNA from the cells is extracted and tested for the presence of genetic disorders. The removal of cells for testing does not affect the development of the embryo, as these cells are restored as the embryo’s cells continue to divide and grow.

The genetics of the cells can be tested by using polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH). PCR is used to look for single gene abnormalities, whereas fluorescence in situ hybridization is used to look for abnormal chromosomes.

Embryos that are not at risk of disease are then transferred into the woman’s uterus where they can be implanted and developed.