Preimplantation genetic diagnosis (PGD) is a technology that refers to procedures conducted before the implantation of an embryo into a woman's uterus. This technology screens the embryo for genetic disease and allows parents to choose which embryo may be implanted.
Preimplantation Genetic Diagnosis
Preimplantation genetic diagnosis consists of procedures such as genetic tests that are conducted on fertilized embryos, or even on oocytes prior to fertilization. This testing can confirm that the resultant baby would be free of the disease under consideration. PGD requires in vitro fertilization in order to obtain the required embryo or oocytes for genetic testing.
It's used to diagnose a genetic defect through in vitro biopsy. An embryo that's not normal isn't implanted in a mother's womb, and a normal embryo is implanted instead.
Benefits of Preimplantation Genetic Diagnosis:
- PGD eliminates the need for termination of an ongoing pregnancy
- There are fewer chances of miscarriage
- You can avoid giving birth to a child with genetic defects
- You can avoid the trauma associated with genetic defects
- It can identify the transmission of a specific inherited disorder in high risk couples
- It is also used in couples at high risk for miscarriage, to increase the chance of continuation of an ongoing pregnancy
Identification of Susceptibility Genes
Preimplantation genetic diagnosis is used to avoid the inheritance of diseases such as cancer, Huntington's disease and sickle cell anemia. Susceptibility genes are identified by this technology and if they're present in the embryo, the pregnancy is not allowed to be initiated or continued.
Human Leukocyte Antigen Matching
Parents who have ailing children that require hematopoietic stem cell transplants use preimplantation genetic diagnosis technology to ensure that the next child is free from such a disease. The newborn could also be a good tissue match for an existing sick child and can donate hematopoietic stem cells to help the sick child recover.
Late Onset Disorders
Parents use the technology to determine whether the embryo can develop into a child who might suffer from a late onset disorder such as Alzheimer's disease. Such embryos are not implanted. Thus, parents can be assured of healthy children who will grow into healthy adults.
Non-Medical Uses of Preimplantation Genetic Diagnosis
Preimplantation genetic diagnosis may also be used by parents who wish that their developing child has certain traits such as intelligence, height, eye color, hair color and texture, and beauty. This will not be possible for quite some time with the existing technology, and there are ethical questions involved as to whether a child should be prevented from existing only because his hair or eyes don't conform to his parents' tastes.
Parents might even wish to be apprised of the sex of the child. Selecting a child on the basis of sex is also unethical, as the selection might favor male children in some countries. This can create social and demographic imbalance in the years to come.
However, concern about how PGD will be used in the future should not be used to prevent the use of this technology in ethically accepted ways.