The ethics of pre-implantation genetic diagnosis

Abstract

Two procedures are being used in many genetics centers for Pre-Implantation Genetic Diagnosis (PGD). In Embryo Biopsy, a single cell from the 4 - 8 cell blastula is aspirated and tested. This implies a post conceptional diagnosis by which fertilized embryos are selected. Only disease-free ones are transferred for uterine implantation. Thus, it suffers from the same moral, ethical and legal constraints that termination does in this country. The alternate procedure, Polar Body Biopsy, merits closer scrutiny in a community such as ours. The genetic testing by which disease-free oocytes are selected for In Vitro Fertilisation (IVF) is done priorto conception. PGD by Polar Body Biopsy has become a viable alternative for couples at risk of having children effected by hereditary disease but who refuse termination or any post-conceptional manipulation. It also improves the outcome of IVF among women of advanced maternal age. World wide, over 2500 PGD cycles have been conducted in the last decade. Five hundred successful disease-free births have been recorded with an error rate of only 1.8% and the same prevalence of malformations as in the general population.