PGD has raised ethical issues. The technique can be used to determine the gender of the embryo and thus can be used to select embryos of one gender in preference of the other in the context of “ family balancing .” It may be possible to make other "social selection" choices in the future. While controversial, this approach is less destructive than fetal deselection during the pregnancy.
Costs are substantial and insurance coverage may not be available. Thus PGD widens the gap between people who can afford the procedure versus a majority of patients who may benefit but cannot afford the service.
PGD has the potential to screen for genetic issues unrelated to medical necessity . The prospect of a “ designer baby ” is closely related to the PGD technique.
By relying on the result of one cell from the multi-cell embryo, it assumed that this cell is representative of the remainder of the embryo. This may not be the case as the incidence of mosaicism is often relatively high. On occasion, PGD may result in a false negative result leading to the acceptance of an abnormal embryo, or in a false positive result leading to the deselection of a normal embryo.
Since PGD and PGH are procedures that can weed out genetically defective human pre-embryos before they have a chance start a pregnancy, the procedure is usually requested by prospective parents who are concerned about passing a serious genetically-based disease or disorder to their child.
Typically,
- one or both partners have been genetically screened previously, and found to be a carrier; or
- one or both partners are from a human population known to have a high incidence of a genetically-based disease or disorder.
If an embryo is found to be genetically defective, it is normally destroyed. This produces a very serious concern for many pro-life supporters who believe that every pre-embryo, embryo and fetus is a human person. Destruction of a pre-embryo is considered a form of murder.
However, there are a number of arguments to support PGD:
- Scientifically, if to combine presently available DNA analysis techniques for screening samples taken both from parents at risk and from sperm/egg bank and IVF, one can produce healthy babies both phenotypically and genotypically. At the same time the disease mutation alleles can be gradually removed from human populations.
- Financially, in comparison with the costly PGD, the above-mentioned approach would considerably reduce the cost for the couples at risk.
- Ethically, it is suggested to keep and apply the ethical regulations at present used for IVF and for other human DNA analysis.
Lecture 36. genetic testing and pharmacogenomics